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Portal 2

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Portal 2
Portal 2 retail cover art. The co-op campaign robot characters Atlas (bottom) and P-Body are featured
Developer(s)Valve Corporation
Publisher(s)Valve Corporation
EngineSource
Platform(s)Microsoft Windows, Mac OS X, Xbox 360, PlayStation 3
Release'Retail'Steam
  • INT: April 19, 2011
Genre(s)Science fiction puzzle-platform game
Mode(s)Single-player, cooperative

Portal 2 is a first-person puzzle-platform video game developed by Valve Corporation. It is the sequel to the critically acclaimed 2007 video game Portal and was announced on March 5, 2010, following a week-long alternate reality game based on new patches to the original game. Though initially slated for release in the last quarter of 2010, the game was postponed to the week of April 18, 2011. The game was released by Valve through Steam for Microsoft Windows and Mac OS X, while the PlayStation 3, Xbox 360 and retail Windows/OS X versions of the game are distributed by Electronic Arts. The game's release on Steam was preceded by a second multi-week alternate reality game involving 13 independently-developed titles, culminating in a distributed computing spoof to release Portal 2 several hours early.

Portal 2 comprises a series of puzzles that must be solved by teleporting the player's character and simple objects using the "portal gun", a device that can create inter-spatial portals between flat planes. Travelling through portals maintains an object's speed and momentum, thus several puzzles require "flinging" the player-character or objects out one portal by gaining speed, such as by falling, before entering the other one. Other gameplay elements were added to Portal 2, including tractor beams, laser redirection, and special paint-like gels, taken from the Independent Games Festival-winning DigiPen student project Tag: The Power of Paint, that imparts special properties to objects it touches, such as increased momentum.

Within the single player campaign, the player returns as the human Chell, having been in stasis for several hundred years, while GLaDOS, a rampant artificially intelligent computer, and the rest of the Aperture Science facility has fallen into disrepair. Chell is awakened by the bumbling Wheatley and inadvertently wakes GLaDOS; GLaDOS is immediately displeased at Chell's return and begins testing her again through numerous chambers as she rebuilds the dilapidated facility. With Wheatley's help, Chell attempts to escape from the facility with the use of the portal gun. With a larger story, Valve introduced additional characters, including Wheatley, voiced by Stephen Merchant, and recordings of Aperture Science CEO Cave Johnson, voiced by J.K. Simmons. Ellen McLain returns to voice GLaDOS. Additional music from Jonathan Coulton and The National appear in the game in response to players' praise from the first game. Portal 2 also includes a two-player co-operative mode in which the player-characters, the robots Atlas and P-body, are part of GLaDOS's "Cooperative Testing Initiative" to seek out data discs outside of GLaDOS's range of influence, and must work together to complete each level using their own individual portal guns.

Portal 2 was universally praised by critics, citing the dialogue and comedy as stand-out elements from the game and applauding the voice work of McLain, Merchant, and Simmons.

Gameplay

Portal 2 continues to challenge players to use portals to traverse rooms in unusual manners, such as flinging, in which the player uses the magnitude of the momentum gained by gravitational acceleration through the blue portal to cross a wide gap out of the orange portal.

Portal 2 is a puzzle game presented from the first-person perspective. Normally, the player, as either Chell in the single-player campaign or as one of two robots, Atlas or P-body, in the co-operative campaign, can move, look, and carry and drop objects. The goal is to maneuver the characters through a number of test chambers in the Aperture Science facility, traversing the chamber from the start to the exit. Though the player-character can take some damage for a brief period of time, they will die under sustained injury and be restarted at a recent checkpoint; however, characters are equipped with "long fall boots" that absorb the shock of landing after a large vertical drop. The player must figure out how to overcome seemingly-bottomless gaps, evade pools of toxic liquid, or avoid line-of-sight or even disable robotic turrets to safely arrive at the exit.

Initial levels provide a tutorial on general movement controls and interactions with the environment. After these levels, the player will be required to solve puzzles in test chambers within the Aperture Science Enrichment Center using the "portal gun" (the Aperture Science Handheld Portal Device), a device that can create two portals connecting two surfaces across space. Players solve puzzles by using these portals to move unconventionally between rooms or to use the ability to fling objects or themselves across a distance. The functionality of the gun has not changed between the games, but within Portal 2, players can take advantage of the bleeding of other physical effects through the portals.[2] One example is the direction of Excursion Funnel tractor beams or Hard Light Bridges through portals to provide surfaces or areas which the player can use to move the player-character or specific objects across obstacles.[2][3][4][5] While early technology demonstrations included the use of Pneumatic Diversity Vents, a series of transport pneumatic tubes, and the interaction of their suction or venting power through portals, these do not appear in the final game.[2][6]

The game also introduces special paint-like gels that can be used to impart certain physical effects to a surface such as Propulsion Gel that boosts Chell's speed as she crosses a surface, and Repulsion Gel that allows her to jump from a surface.[7] A third gel type, Conversion Gel, allows any surface coated with it to accept portals.[8] The player will be required to determine how to transport that gel to appropriate surfaces using portals in order to progress.[2] The gels can also be applied to objects, such as the Weighted Storage Cube crates, that affect their own physical nature.[2] In addition to the Storage Cube, there are new types of objects that assist the player, including Redirection Cubes with mirrored, reflective surfaces used to redirect Thermal Discouragement laser beams, Aerial Faith Plates that can launch objects placed on them, and spherical Weighted Storage Balls, which made a brief appearance in the original game in one of the advanced chambers.[2][6] The heart-decorated Weighted Companion Cube, used by GLaDOS in the first game to make Chell form an emotional bond to the inanimate object before incinerating it, also appears in the sequel.[9]

While most of the single-player game takes place in the test chambers created by GLaDOS or her personality cores, there are times where the player will need to move behind-the-scenes in areas beyond the test chambers as they are reconfigured, leaving the player free of GLaDOS's observation and control.[2]

The game includes a two-player co-operative mode in addition to the single player mode.[10] This mode can be played by two players at the same computer/console via split-screen, or through two remote players at their own computer/consoles; Microsoft Windows, MacOS X, and PlayStation 3 users can play with each other regardless of platform. Both players control separate portal guns and can use the other player's portals as necessary;[2] each player's portals are of a different color scheme (blue/purple, and orange/red) to help distinguish between the two sets.[5][11] Because of the number of possible portal combinations, the test chambers that the players proceed through are much more difficult than the single-player campaign, requiring the two players to work together. Initial chambers set each robot in their own separate section of the chamber, and their solutions teach the use of the communication tools and portal use to complete. Latter chambers are less structured, and require the players to use both sets of portals for laser or funnel redirection, launches, or other maneuvers to reach the exit.[12] Should either robot die, a new robot will be recreated shortly after, allowing players to continue on the puzzle without restarting.[13] The game includes voice communication between players for this mode as well as split-screen for players playing locally. Online players have the ability to temporarily enter a split-screen view to help coordinate actions.[11] Players have the ability to "ping" walls or objects on the game's levels as a means of informing the other player what they need to do, starting countdown timers for concerted actions, and perform emotes with their partner, such as waving or hugging.[2][4][12] Borrowing on the concept from Left 4 Dead, players, both in the co-op and single player campaign, can see the outlines of placed portals through walls and other obstacles to identify their locations.[14][15] The game tracks what chamber each player has completed, and allow a player to replay chambers they have completed with other partners who may have not yet completed that chamber.

Valve has stated that both the single player and the co-operative campaigns are about each 2 to 2.5 times as long as the original campaign in Portal, with the overall game five times longer than the original.[4][16][15] Erik Wolpaw estimates each campaign is about six hours long.[13]

As with previous Valve games, Portal 2 contains in-game commentary from the game developers, writers, and artists.[17] The commentary, accessed after completing the game once, appears on node icons scattered through the game's levels, either where the development team found significant changes from their original ideas, or where ideas failed to work out for the game.[17]

Plot

Portal 2 takes place after the first game; as part of the Half-Life series, some time after Half-Life 2.[18] Despite her apparent destruction at the end of Portal, GLaDOS, an artificial intelligence computer system, remains functional but dormant. The player controls Chell, the previous protagonist of Portal. Retroactively patched just prior to the sequel's official announcement, the ending of the first game shows Chell being dragged away by an unseen figure with a robotic voice, later identified by writer Erik Wolpaw as the "Party Escort Bot",[19] after which she is placed in stasis for a period of many years.[2] The game again takes place in the Aperture Science Labs, untouched by human hands but overrun by decay and nature.[2] One hidden area of the game shows the former location of Aperture Science's cargo ship, the Borealis, in the bowels of the facility; this ship is mentioned as part the Half-Life universe at the end of Episode 2, having been discovered in the Arctic, situated in an seemingly-impossible position with all hands lost. Portal 2 suggests the ship was related as a result of an experimental teleportation device being developed by Aperture to compete with Black Mesa, the research facility featured in Half-Life.[20]

An abandoned area in Portal 2, showing the effect of flora overgrowth and deterioration on the Aperture Science facilities. The art on the wall, created by the "Rat Man" character, depict the events of the first game, and also tie in with the "Lab Rat" comic.

Parts of the story are bookended by the "Rat Man", an unseen character in the first game whose background is fleshed out in an online comic "Lab Rat" produced by Valve to tie the history of the games together. Rat Man, a scientist at Aperture, escaped from the neurotoxin released by GLaDOS that wiped out the rest of the Aperture staff, and slowly became insane. However, he sees that Chell is unique for her tenacity among the thousands of test subjects stored by Aperture, and seeks to protect her, moving her to the top of the list subject queue to allow her to escape. He wrote messages on walls to guide and warn Chell during the events of the first game; having witnessed GLaDOS's defeat at the end of the first game, the Rat Man's drawings created in the months after the events summarize the first game during Portal 2's introduction. Rat Man, though able to escape after GLaDOS's destruction, returns to the facility following the robot that drags the unconscious Chell back inside. As a final act, he ensures that Chell is kept in indefinite cryostorage, before he himself enters a cryogenic unit after being severely wounded by turrets.[15][21][22][23]

Main campaign

At the start of the game Chell finds herself in what appears to be a motel room. After a robotic voice guides her through a cognitive test she is put to sleep. When she next gains consciousness, the decay of the room's decor implies many years have passed. Wheatley (Stephen Merchant), a personality sphere, helps Chell to escape as the room—located in one of hundreds of shipping containers among a giant warehouse—shifts and moves, and she finds herself back in the test chambers of the Aperture facility.[24][25] Wheatley is one of many personality cores which have become active and gained independence from GLaDOS in the intervening years, using the automated systems of Aperture Science to create their own microcosms within the facility.[2] Wheatley has become concerned about the state of decay and seeks to correct it, guiding Chell during the tutorial and initial stages. Soon, the two encounter the dormant GLaDOS (Ellen McLain) and accidentally wake her; she accuses Chell of "murdering" her years ago.[2] GLaDOS begins to rebuild the ruined facility, and puts Chell under more tests, stating "I think we can put our differences behind us. For science. You monster."[26][27]

Wheatley instructs Chell to play along with GLaDOS through her test chambers while he locates the central turret manufacturing plant and neurotoxin facility. He distracts GLaDOS long enough to bring Chell to these facilities to disable them and take her to the reconstituted GLaDOS. Without threat of the turrets or neurotoxin, Chell is able to exchange Wheatley's personality for GLaDOS's. Wheatley, now able to access the power of the entire facility, turns on Chell, placing GLaDOS's personality into a module powered by a potato battery, and sends both Chell and GLaDOS miles deep into the bowels of the facility. As they fall, GLaDOS chastises Chell for putting Wheatley in the position of power, claiming that he was "the product of the greatest minds of a generation working together with the express purpose of building the dumbest moron who ever lived", designed to hamper GLaDOS's decision-making processes.[28]

After landing, GLaDOS is abducted by a bird, while Chell works to climb back to the higher levels through a series of chambers automated by recordings of Aperture Science's CEO, Cave Johnson (J. K. Simmons).[29] During her climb through the various strata of old Aperture test chambers, Chell learns that Johnson became further deranged from poisoning from moon dust, a key component for the paint necessary for portal technology. As a result of this and further competition with Black Mesa, the company devolved from its original intent and became solely focused on simply testing subjects for science, originally using elite personnel from the military, to paid volunteers, and finally to mandatory participation from its employees, a testing protocol was ingrained in the core of GLaDOS's programming.[29] Chell also discovers that GLaDOS's intelligence derives from Cave's personal assistant Caroline (McLain), who was a test subject for a mind-to-computer transfer system; some point after this process, a dying Johnson placed her in charge of Aperture. Chell and GLaDOS are reunited, and they form a truce to stop Wheatley before he destroys the Aperture facility from his incompetence.[30]

Chell and GLaDOS eventually reach the main facility again and face Wheatley, though GLaDOS's ploy to confront him with a paradox fails miserably. Wheatley, influenced by GLaDOS's core protocols, puts them through most deranged test chambers, ignoring the warnings about the fatal collapse of the facility.[31] They eventually break free and confront him. GLaDOS initiates another core transfer while Chell distracts Wheatley by adding defective core modules.[32] As the facility's roof collapses, Chell shoots a portal at the moon, sucking her and Wheatley into space. GLaDOS manages to pull Chell back inside while leaving Wheatley to be stranded. Some time later, Chell wakes up, where GLaDOS then introduces her to Atlas and P-Body, a pair of robots designed for cooperative testing, and explains she learned valuable lessons about humanity from her Caroline persona.[32] She then deletes this aspect of her personality, reverting to her standard antagonistic attitude, but finally allows Chell to leave the facility, explaining that though she could continue to test Chell, she fears for her own safety from Chell's destructive nature. The game ends with Chell and her battered Weighted Companion Cube exiting the facility into a wheat field. In the epilogue, as Wheatley floats aimlessly through space, he begins to voice regrets about betraying Chell.[32]

Co-op campaign

Two new characters are introduced in the two-player cooperative mode, which has its own unique plot and setting.[10] These two characters are Atlas and P-body, a modified personality core and turret gun, respectively;[33] both units are bipedal and equipped with their own portal guns.[2] Though once part of the networked facility, they have become separate entities and are treated to similar abuse by GLaDOS through a series of complicated test chambers through her "Cooperative Testing Initiative".[2][34] The robots make "expressive noises" in place of distinguishable dialogue, first stated by Valve's Doug Lombardi.[35] From previews, the robots' mannerisms suggest a double act similar to Laurel and Hardy, according to some journalists.[4][36] GLaDOS appears to be troubled by the robots working together, and will attempt to aggravate their relationship through verbal trickery such as praising one robot over the other.[4] Though the co-op story takes place chronologically after the single player campaign and has some ties into it, Wolpaw claimed that players "don't need to necessarily need to [sic] play them in that order".[37]

In the co-op campaign, Atlas and P-body are shown to five sets of test chambers by GLaDOS. In the first four of these, GLaDOS prepares the robots to "venture outside" of the test systems of Aperture Laboratories to recover a data disk, after which she destroys them, restoring their memories to new bodies, as it is the only way she can recover them from "outside". Collectively, the data points to the location of "the Vault", where GLaDOS claims humans can be found. At the conclusion of the fifth test chamber, the robots discover and gain entry into the Vault, a giant structure where thousands of human bodies in cryogenic suspension are found. GLaDOS gleefully congratulates the robots, seeing the humans as new test subjects for her to process.

Development

Valve's Doug Lombardi commented that Portal was originally included as an add-on product to The Orange Box as, to Valve, it was a piece of trial software and had considered The Orange Box as a safety net if it failed; Lombardi stated, "There was no way we could have planned for the success of Portal."[2] After receiving high praise and proving its worth, Valve determined that Portal 2 should be its own product, committing more resources than it did for the first game for its release.[2] Compared to the previous Portal team that consisted of about 8 people, Portal 2 had a dedicated 40-person staff working on its development.[38][39] Valve President Gabe Newell has stated that they know what players are looking for in the full sequel, and expect that Portal 2 will be "the best game we've ever done."[40] Project manager Erik Johnson commented that the first Portal caught people by surprise and "made them think about games in a different way".[27] Johnson believed their goal with Portal 2 was to find a way to "re-surprise" players, and considered that a "pretty terrifying" prospect.[27] Original Portal designer Kim Swift, however, has left Valve to join Airtight Games.[41]

Design

Portal 2 introduces paint-like gels that affect the physical nature of surfaces they coat. Here, the blue Repulsion Gel, carried over the turret guns by the faint blue Excursion Funnel beam, causes the painted turrets to bounce off any other surface.

Work on Portal 2 began almost immediately after the release of Portal in The Orange Box.[38] Initial ideas for Portal 2 considered dropping the portal aspect from the game; instead, the player would still participate in Aperture Science Laboratories testing a device centered around a new type of physics-based puzzle. When Valve presented these ideas to others for comment, the lack of portals was criticized. Valve therefore returned to the portal mechanic and sought what other physics mechanics could be incorporated with portals into the larger game.[13] One of these was a gel mechanic that can alter the physics of surfaces coated with that gel. Valve found that this addition gave players more control over the game world, but as a result, required the chamber designer to be more devious with their solutions to account for the various possibilities of the gel mechanics.[42] The gel mechanic comes from Tag Team's Tag: The Power of Paint, a DigiPen student-developed game that won the 2009 Independent Games Festival Student Competition prize. Valve's vice president of marketing, Doug Lombardi, said that upon viewing the student game then, "the decision to combine their tech with Portal 2 came naturally".[35] Wolpaw recalled that they had already considered the nature of surfaces in Portal in a binary fashion, whether or not it would allow for a portal to be created on it, and the ability to modify surface properties in the manner that Tag did was an obvious extension on that.[38] Subsequently, Tag Team was hired by Valve, though initially their work was to "develop Tag in an interesting way", according to Wolpaw, only some time later being brought into the Portal 2 team.[35][38] The Tag Team members were able to work out the interaction of the paint mechanics with portals, leading to new types of puzzle features in the game.[13] Journalists compared this to the evolution of Narbacular Drop, another DigiPen student project, into the basis of Portal.[43][44][45] While Tag features three paint types, only two have been shown to be included with Portal 2; the third, one that allowed the player to walk on any surface coated with the paint, was originally included, but this induced motion-sickness in playtesters and was dropped.[46] Instead, new gel types were designed to be included in the game, according to Wolpaw, ultimately leading to the white Conversion Gel.[13][8] The gels themselves are rendered using new fluid dynamics routines included in the engine to simulate their blob-like nature.[19]

Several of the early test chambers in Portal 2 reused the original chambers from Portal, adding deterioration and aging to provide familiarity to the player while suggesting the length of time between the two games.

Portal 2 was designed to give the player incremental steps in understanding portals and their use within the game.[42] This approach led to two basic types of chambers. The first type, which Valve calls "checklisting", provides a relatively safe environment for the player to experiment with a fundamental aspect of a new gameplay concept. The second type of chamber is one that combines these elements in new ways to make the player think laterally, giving the player a rewarding experience for completing the chamber.[42] Chambers were first developed through whiteboard via isometric drawings, with the developers performing a sanity check on the chamber, before being created into simple levels through the Hammer level editor. Extensive playtesting was used to make sure the solutions to each chamber were neither overtly obvious nor difficult to see, and to observe alternative solutions discovered by playtesters; based on their input, the design team would keep these alternate solutions viable within the level, or would work around and block the alternate solutions if they were too easy.[42] Once a chamber was considered ready to proceed, the Valve artists then would add elements such as detailed texturing, dynamic lighting, and vegetation, using an advanced version of the Source engine.[15] These versions would then be sent back for further playtesting to verify the new elements did not prevent players from finding proper solutions, with further iterations between artists and playtesters until such issues were resolved.[42] Several early chambers the player experiences in Portal 2 were created by reusing the Portal test chambers, and applying decay, collapse, and overgrowth on them. As an initial goal in the sequel, this was done to give players a sense of nostalgia from the first game and a feeling for how much time has passed. It also allowed the team to avoid the use of the less-resolved textures from the first game, replacing them with higher-resolution dirty and worn-out textures that the newer engine could support.[47] Portal 2 also contains advanced rendering techniques for liquids that were developed from Left 4 Dead 2. Portal 2 combines the concepts of "flowing" surface maps to mimic the motion of water in a setting, along with "debris flow" maps and random noise to create realistic real-time rendering of water effects.[48] Johnson stated that Valve's aim was not to make Portal 2 more difficult than its predecessor, but instead wanted to keep the same idea of a game "where you think your way through particular parts of the level, and feel really smart when you solve it".[27]

The co-operative gameplay came about from requests from players as well from anecdotes of players working together on the same computer or console to solve the game's puzzles, likened by Wolpaw to players working together on the same computer to solve point-and-click adventure games.[27][35][38] The co-operative campaign was also inspired by Valve's Left 4 Dead co-operative games, where players would find enjoyment after playing the game, discussing their personal experiences with the game.[14] While the single player campaign in Portal 2 is designed to avoid frustrating the player, the co-operative levels are more focused on coordination and communication, and are recognized by Valve as being much more difficult than the single-player puzzles.[49] Valve had avoided including timed puzzles into the single player experience in both Portal and Portal 2, but found that the inclusion of these into the co-operative mode was effective, giving players a positive feeling after being able to plan and execute difficult maneuvers.[13] Other puzzle elements, such as the light bridges, are further inspirations from Left 4 Dead.[14] Each puzzle chamber in the co-operative mode was assured of requiring four portals to solve as to prevent puzzles being solved by only the actions of one player; as soon as someone discovered a way to complete a puzzle with one set of portals, the level was sent back to the drawing board to correct this.[13][19] Except in few cases, the chambers were designed where neither player would remain out of sight of the other in order to promote communication and cooperation. Some of the puzzle chambers were designed as asymmetric chambers, where one player would manipulate portals and controls to allow the other player to cross the room, helping to emphasize that the two characters, while working together, are also separate entities.[13] The ability to tag surfaces with instructional icons for one's partner was soon realized as a necessary element, as it was found to be much more effective for cooperation than through simple verbal instruction.[38]

In addition to the cooperative mode, Valve had considered a competitive mode. According to writer Erik Wolpaw, the mode resembled a variation of speedball where one team would attempt to transport a ball from one side of the playing field to the other using portals, while the other team would attempt to stop them with their own use of portals. While Wolpaw said the matches would begin with this objective in mind, they would quickly descend into chaos. Instead, they realized people enjoyed solving puzzles with portals more, and focused on the cooperative mode.[50]

Art, writing, and casting

File:Portal2-chell.jpg
Chell, the player-character, was given a new look, retaining her orange jumpsuit from the first game but partially disrobed, to make the character stand out as an individual. Chell equips the portal gun in her hands, and long fall boots to reduce the shock from falling large distances.

Erik Wolpaw returned to write out the game's script in addition to Chet Faliszek, main writer for the Left 4 Dead games and past Old Man Murray partner with Wolpaw, and National Lampoon veteran Jay Pinkerton.[2] Valve has stated that the game contains over 13,000 lines of dialog between the single player and cooperative campaign.[51] The game's story was developed in tight coordination with the gameplay, developing the plot alongside each testing build for the game.[52]

"Well done. Here come the test results: 'You are a horrible person.' That's what it says. We weren't even testing for that."

—Example dialog from GLaDOS in Portal 2[28]

Portal 2 was initially envisioned to be a prequel for the first game, years before GLaDOS's takeover of the Aperture Science facility, but eventually became a sequel set hundreds of years after Portal.[46] The story for Portal 2 mirrors ideas from the first game; to contrast the destruction of the Aperture Science facility by the player in Portal, the new game starts with the reconstruction of the facility by GLaDOS.[38] This helped to create the image of Aperture Science as a "living, breathing place", with GLaDOS given full control to restructure and arrange the setting as she needed it, according to Wolpaw.[38] While they introduced new characters into the game, the focus of the story in Portal 2 remained the connection and interaction between Chell and GLaDOS, and focuses more on the fallout from Chell's destruction of GLaDOS from the first game.[38] In considering the interaction between Chell and GLaDOS, Johnson compared GLaDOS to "a jealous ex-girlfriend", noting "[Chell is] the only person she can have interaction with, but the problem is her only way of interacting with anyone is to test them".[17] Wolpaw also compared GLaDOS to The Sopranos character of Livia Soprano, being "incredibly passive-aggressive and mildly sarcastic".[53] GLaDOS introduces each chamber and congratulates the player on completing it; though they could have included intermediate dialog from GLaDOS while the player attempts to solve each chamber, they found this would be distracting to players, and limited her presence in the game to only these points.[42] GLaDOS continues to be voiced by Ellen McLain, who worked with Valve every two weeks to record the majority of the dialog for the game.[53] The frequency of her voice sessions allowed Valve to experiment with GLaDOS's lines and how they came out within the final game.[53]

Valve originally had explored using other characters for the protagonist in Portal 2 before returning to the silent player-protagonist character of Chell from Portal.[54] In early playtesting for the game, Valve had omitted Chell, believing her story to have been done with Portal, and introduced a new player-character; though playtesters were able to accept playing as a different character for the first part of the game, they became disoriented when GLaDOS did not recognize their player-character. Valve reintroduced Chell as the player-character, believing that it was not so much the specific character but the "continuation of the player's experience", and what they did to GLaDOS in Portal that was valued, according to Wolpaw.[19][55] Early envisioning of Chell included a more utilitarian outfit, something that would have been designed by a computer for identifying and tracking its test subject.[54] These images also included a hat, envisioned by the artists to help to keep Chell's appearance as a test subject similar to test pilots, as well as adorned with the number 6 to serve as a tracking means for the facilities' computers.[54] However, later in development, they returned to the orange "dehumanizing" jumpsuit used in the first game, but now partially disrobed to the waist, giving the sense of more freedom of movement.[56] This gives Chell the appearance of standing out as an individual compared to being a numbered test subject, according to Valve's art team.[56] The reuse of the jumpsuit gives those people that have played Portal a sense of familiarity while reflecting the changes in the Aperture Science center.[56] They also designed Chell to appear physically capable of completing the test chambers, but with some vulnerability.[54] As in the first game, Chell's facial appearance is based on voice actress Alésia Glidewell.[57]


Stephen Merchant (top) voices Wheatley, the personality sphere, while J.K. Simmons (bottom) voices Cave Johnson, the eccentric CEO of Aperture Science.

Personality spheres represent new characters within the game; Johnson contrasted them to non-player characters from Half-Life 2, as the personality spheres are "story-delivery type of character[s]" help to establish more of the game's backstory than they could do in Portal.[17] The writing team noted that the use of the personality modules allowed them more freedom than in other games for developing these as characters; they would not require facial or body animations, and they could envision the use of more recognizable voice actors for each module.[58] Although they initially thought of using six or so modules throughout the game, they decided to simplify the story and stuck to a single module, Wheatley.[59] At the 2010 E3 conference, the demonstration version included the voice of Valve animator Richard Lord for the Wheatley personality sphere; Doug Lombardi noted that the audio was simply a placeholder for the demo, but Lord's performance was well-received and made the character as likable as the Weighted Companion Cube from the first game, urging critics to request Valve retain Lord's voice in the final game.[60] Valve eventually revealed that Stephen Merchant voices Wheatley in the shipped product.[61] Part of their selection of Merchant was based on his "vocal silhouette" to distinguish the Wheatley character from GLaDOS; to contrast from the slow deliberate pace of GLaDOS's lines, Wheatley is meant to be more "frantic", a quality that Merchant's voice work was able to bring.[14] They also wanted Wheatley to speak informally, with dialog that seemed as if it was created on the spot in response to occurring events, and considered Merchant's ability to ad lib and to provide a lot of information in a short period of time while still being understood to be strengths for the character.[15] They had envisioned a British voice from the start, having been in contact with The IT Crowd's writer Graham Linehan to try to get Richard Ayoade to perform the role, but later stuck with Merchant who they felt was a better match.[15] Merchant spent about 16 hours over four sessions to record his lines; they gave Merchant the ability to play around with the dialog to voice in the manner he best felt suited the role.[19][29]

Another character, the voice of Aperture Science's founder and CEO, Cave Johnson, is portrayed by J.K. Simmons as announced at the 2011 PAX East exposition.[62] Johnson was envisioned since Portal as a "industrial, Southern guy" who would contrast the "anti-septic" and "politically correct" nature of Aperture Science.[19] Though their idea of the character underwent several changes over the development, the selection of J.K. Simmons helped to solidify the character.[19] Pictures of Cave Johnson appear throughout Portal 2, and though Valve used a casting call to try to find someone to use as a template, they turned back to their own lead animator, Bill Fletcher, for Cave's face.[46] The writers found they needed another character to play off of Cave during his recordings; instead of hiring a voice actor for a few lines, they economized by reusing McLain to play Caroline, Cave's assistant. This led naturally to providing a backstory for the creation of GLaDOS, who is revealed in-game to be based on Caroline's personality.[63]

Though new characters were introduced, Wolpaw stated that they wanted to maintain the one-on-one relationship between each character with the player-character.[19] Even when they had two characters talking to each other, they wanted more to have the player simply be a silent observer for the conversation, and made the situations more engaging while the dialog continued.[19] Wolpaw also identified that, in the end, the three characters of GLaDOS, Wheatley, and Johnson contrasted well with each other.[19]

Wolpaw and Faliszek also consider the Aperture Science facility as its own character within the game.[21] Faliszek described Aperture Science as "a science company that's gone mad with science, where they put that first in front of everything else".[21] Though parts of the history of Aperture Science were revealed within the first game and through ancillary materials associated with it, Faliszek says that the player will learn more about the company including "lot of the behind-the-scenes stuff".[21] Parts of this are through triptych-like artwork left behind by the Rat Man character, which the player sees at the start of the game and in playing through some levels.[21] Rat Man's art has been created by in-house artist Andrea Wicklund, who was assigned to develop the graffiti-like style for the game.[21] Though never named within the game, the Rat Man character will be further developed in "ancillary" material outside of the game surrounding the game's release.[15] One such path is the release of a two-part comic, "Portal 2: Lab Rat", developed in-house by Valve with the aid of Michael Avon Oeming, who had previously helped Valve with comics for Team Fortress 2 and Left 4 Dead. The comic, made available online about two weeks before Portal 2's release, includes Wicklund's art contrasted against Oeming's own style and layout, along with an overall story written by Ted Kosmatka. The artists worked with the game's writers, Laidlaw, Faliszek, Wolpaw, Pinkerton and team leader Josh Weir to tie the comic's story, taking place between the two games, to the plot of Portal 2.[64][22][23]

The co-operative campaign contains a separate story between the two robotic characters and GLaDOS. The co-operative campaign includes additional dialog from GLaDOS; the original dialog Wolpaw wrote for GLaDOS was aimed to two women, Chell and a new character "Mel", with the assumption of "image issues", but this dialog remains in place even after the change of the co-op characters to robots.[49] The dialog written for GLaDOS in the co-operative campaign is aimed to try to break the bond between the two robot characters. Valve considered initially to have separate lines for GLaDOS that would be given to each player individually, but found this to be a significant effort for minimal benefit. The writers also attempted adding GLaDOS lines that would make the players attempt to compete against each other, such as the awarding of meaningless points, but playtesters did not respond well to these lines.[13] Faliszek noted that in co-operative games, it can be difficult to deliver key dialog or in-game events to the unpredictable players, who may not been looking in the right direction at the right time; instead, using lessons learned from Left 4 Dead, Faliszek and Wolpaw kept the story and key comedic lines short but frequently repeated.[65] The two robotic characters created for the co-operative mode were originally based on designs similar to the movie Westworld, looking more human and less robotic. They eventually redesigned the two characters as a modified personality sphere and turret gun, reflecting the character of the Aperture Science facility. This change also took into account the likely numerous deaths players would endure while trying to solve the puzzles together; with human or human-like characters, the deaths would be rather gruesome, but with robotic characters, Valve was able to provide more comical animations as the robots met their fate, such as struggling from being crushed by a lowering ceiling.[49] The artists found the robot design alone related much of the character's background, in part due to the imagery from the previous game, as well as emphasizing the co-operative mode through the robots holding hands.[54]

The indie rock band The National composed a new song, "Exile Vilify", for inclusion in Portal 2.

After finding that Jonathan Coulton's song "Still Alive" was a large part of Portal's success, Valve included more music in Portal 2, including further involvement from Coulton.[2] Coulton wrote a new song for the game's ending credits, "Want You Gone", which is written from GLaDOS's viewpoint of wanting to rid herself of Chell.[66] Another original song, "Exile Vilify", was provided by the indie rock band The National.[67][68] The National had expressed interest to Bug Music, their publishing label, in doing music for Valve, which the label forwarded on to Valve in discussing other music opportunities for the game. Valve and Bug Music identified The National would fit well into Portal 2, as their "raw and emotive music evokes the same visceral reactions from its listeners that Portal does from its players" according to Bug Music's spokesperson Julia Betley.[69] Other music in the game is procedurally generated, generated in real-time based on the player's actions; Mike Morasky, the game's lead composer, claims that one track of music will only be heard every "76,911 years, 125 days, 7 hours, 56 minutes and 30.3 seconds".[46] Wolpaw commented that while many story elements of Portal are revisited in the sequel, he will likely not return to some of the memes, such as "the cake is a lie", that have been retread over the past few years; Wolpaw stated, "If you thought you were sick of the memes, I was sick of it way ahead of you".[70] However, Wolpaw stated that "we couldn't resist putting in just one" cake joke within the game.[15] Faliszek stated that they did not attempt to predict or write to lead to any other memes, believing that "you can't really plan for [dialog to become a meme] because if you do it probably seems weird and forced".[71] There are separate ending sequences for both the single player and the co-operative campaign, including different surprises similar to "Still Alive".[72]

Announcement

File:Portal-2-ARG-SSTV-Images.png
Part of the alternate reality game that led up to Portal 2's announcement was the decoding of SSTV images embedded in an update of the original game.

After Portal's release and critical success, Valve employees Doug Lombardi and Kim Swift, indicated that "more Portal" will be coming.[73][74][75] Swift suggested the sequel may contain a multiplayer element, but only if this "from a technology standpoint is possible".[76] Previous comments from Swift had suggested that a multiplayer Portal was "less fun than you'd think."[77] On June 10, 2008, Kotaku reported that Valve was seeking voice actors for the character role of Aperture Science CEO Cave Johnson and suggested that the second game may be a prequel to the events in Portal.[78] However, a later update suggested it could be a sequel, with Johnson as another AI.[79]

The sequel was officially announced on March 5, 2010, but events within the week before this foreshadowed the announcement. On March 1, 2010, a patch was released for Portal. The patch included an additional achievement, "Transmission Received", requiring the player to manipulate the in-game radios in an appropriate manner. This revealed new sound effects that became part of an alternate reality game-style analysis by fans of the game;[80] the effects included Morse code strings that implied the restarting of a computer system, and SSTV images from a grainy Aperture Science video. These images embedded further hints of a BBS phone number that when accessed, provided a large number of ASCII-based images relating to Portal and segments of fictional documents for Aperture Science; many of these ASCII pictures were published art assets for the game as shown in the Game Informer reveal of the title.[2] A second patch two days later altered the game's original ending to suggest Chell's current fate, with additional digital files and resources to further the alternate reality game.[81] These events were seen by gaming journalists to be leading to a forthcoming Portal 2 or other Half-Life game announcement.[82][83][84] Following these events, in time with a countdown timer on the BBS, Portal 2 was officially announced.[85] Details of this alternate reality game were embedded in additional SSTV audio-encoded images within a hidden room within Portal 2. According to these, the game only had a budget of $100 to produce and designed to attract both casual players via the finding of radios in Portal, and the more enthusiastic players through the decoding and deciphering. The BBS was based on a personal computer being run out of the kitchen of one of Valve's employees as the Valve office phone lines were too modern to support a BBS.[86]

Gabe Newell continues the alternate reality game surrounding Portal 2's announcement during the 2010 Game Developers Conference.

The alternate-reality game continued after the game's announcement. New ASCII images continued to appear on the BBS after the official announcement. At his acceptance speech for the Pioneer Award at the 2010 Game Developers Conference, occurring the week following Portal 2's announcement, Gabe Newell ended his speech presentation with a fake blue screen of death, purporting to be from GLaDOS and hinting at further Portal 2 news at the Electronic Entertainment Expo 2010 (E3).[87] Two weeks prior to Valve's planned presentation at E3, a cryptic e-mail received by game journalists, purportedly sent as a press release from Aperture Science, hinted that the presentation of Portal 2 was canceled but was to be replaced with "a surprise" jointly by Aperture Science and Valve; this has led to some speculation that Half-Life 2: Episode Three may be announced alongside further reveal of Portal 2.[88] In the week prior to E3, Valve reiterated that the "surprise" at E3 would still be about Portal 2, but noted that the game's release has slipped to sometime in 2011, humorously referring to the preservation of "the fabric of Valve Time".[89] The surprise at E3 was revealed to be the development of the PlayStation 3 version of Portal 2 with partial support for Steamwork on the console, a dramatic reverse of Valve's previous statements on the console.[90][91][92]

PlayStation 3 support

As part of the Sony press conference at E3, it was revealed by Newell that Portal 2 will be available for the PlayStation 3 and will be the only console version to include some features of Steamworks used in the PC and Mac versions, making the game in Newell's words "the best console version".[90] The news came as a surprise to many journalists,[91][93] as previously, Newell has made negative comments about the system, calling it "a total disaster on so many levels" in reference to the difficulties in porting The Orange Box to the console.[92] Newell jokingly referred to these comments by thanking Sony for "their gracious hospitality and not repeatedly punching me in the face", and said that he was nervous because he was introduced to Sony marketing character Kevin Butler as the "VP of sharpening things".[94]

Portal 2 is the first game on the PlayStation 3 to support a subset of features from Steamworks, including auto-updates, downloadable content, and community support.[95] The game supports cross-platform play between the PlayStation 3 and the Windows and Mac OS X versions, allowing users to save their game in the Steam Cloud to reuse on any of these three platforms;[96] this was a sought after goal with the use of Steamworks on the PlayStation 3.[97] On the PlayStation 3, the Steam overlay shows the player's friends on both Steam and the PlayStation Network, and achievements earned in Portal 2 are rewarded for both Steam and PlayStation Network trophies.[98]

Because of the integration of Steamworks on the PlayStation 3, Valve is able to collect data on bugs and other problems that may arise after shipping, and can release patches regularly to fix these or normalize features across the three Steamworks platforms.[15] Valve stated they did not plan on integrating other PlayStation 3 features, such as 3D television or PlayStation Move support.[99] Despite some reports that Move support would be included,[100] Valve has clarified that the game will not support Move.[101] Valve contrasted this to the support the game has for the Razer USA Hydra Motion Controller, including additional levels designed specifically for the controller;[102] according to Faliszek, the Razer developers spent nine months in-house with Valve to help bring in the controller compatibility with the Microsoft Windows version, while they would have needed a similar level of effort to incorporate the PlayStation Move controller.[103] Faliszek further explained that the initial reports on the Move support were due to a translation error during an interview.[103]

Downloadable content

Similar to Team Fortress 2, the co-op mode includes a means of customizing their bot characters through cosmetic items like hats or flags earned in-game, trading with another player, as part of Steam sales promotions, or bought through funds in an in-game store.[104]

Portal 2 supports end user-made levels on the Windows, Mac OS X, and PlayStation 3 (made available by Steamworks), while Valve provides more direct support for these levels on the Xbox 360; some reporters believe they use a similar method that the developers used for Super Meat Boy to bypass the Xbox Live Marketplace for additional content.[105] The tools to make these levels will only be available on the Windows platform due to software dependencies.[72]

Promotion and release

Portal 2, on its March 2010 announcement, was originally set for release late 2010.[106][2] In August 2010, Valve announced that the game's release had slipped to February 2011, with a planned Steam release date of February 9.[107] Valve announced a further delay of the game in November 2010, setting the week of April 18, 2011, for release worldwide through retail and online channels.[108] On February 18, 2011, Newell confirmed that Valve had completed the development work on Portal 2, and that they were "waiting for final approvals and to get the discs manufactured" in anticipation of this release date.[109]

Portal 2 is the first Valve product simultaneously released for Windows and Mac OS X computers through the Steam platform.[110] Retail copies of the game for Windows, Mac OS X, Xbox 360, and Playstation 3 are distributed by Electronic Arts.[111] As part of the PlayStation 3 release, those who purchased the PlayStation 3 version of Portal 2 are able to unlock the game on the Steam platform for Windows and Mac OS X for free by linking their PlayStation Network and Steam accounts, and using a redeemable code within the PlayStation 3 packaging.[96][98] Faliszek explained that despite the additional support for the PlayStation 3 version, "the core game, whether you buy it on PS3 or 360 is the same, you're not going to lose out anything on that".[112]

Portal 2 will be bundled as part of the release package for the Razer USA Hydra motion controller for personal computers in mid 2011.[113] In conjunction with Valve, Razer USA developed additional Portal 2 levels to be used specifically with the motion controller.[102]

Valve created their own series of television commercials for promoting Portal 2. According to Lombardi, though they had worked with advertising agencies in the past to create advertisements, Valve found the agencies to provide little ingenuity towards their games; Lombardi's frustrations included "Copycat treatments. Cliché treatments. Treatments that reveal the agency wasn't listening in the initial meeting."[114] By creating the ads themselves, Valve was able to tailor the content based on feedback until they were satisfied with the results. The ads took eight weeks to complete.[114] Valve also developed additional online promotional videos, featuring J.K. Simmons narrating as Cave Johnson to promote new elements of Portal 2's gameplay. These videos were part of a larger effort described by Newell as a "documentary-style investment opportunity" for Portal 2.[115]

At the PAX East exposition in March 2011, Wolpaw stated they would provide material before the game's release to tie the timeline between Portal and Portal 2 together.[116] The forementioned "Lab Rat" comic, produced by Valve, providing a tie-in story between Portal and Portal 2, was released about two weeks before Portal 2's availability.[22][23] Valve also offered new Portal 2-themed merchandise on their own store, such as t-shirts, including one that parodies the Three Wolf Moon shirt, posters, and drink glasses.[117]

Portal 2's release was preluded by another alternate reality game supported across thirteen independently-developed games included in a Steam software sale called the "Potato Sack" launched on April 1, 2011. The idea of the "Cross Game Design Event" was from Newell in December 2010, and Jeep Barnett, one of Valve's programmers, worked with the independent developers to set the ultimate goal of the promotion, but letting the developers themselves plan out the game, giving them full access to art assets from Portal and Portal 2.[118] Though several of the games jokingly replaced some assets with potatoes or variants of this, gamers found symbols, text phrases, graphics, and other art aspects that seem unrelated to the games themselves. One asset includes a map of a research facility that is similar to what players witnessed at the end of Portal, while other assets seem to be phrases that GLaDOS would state.[119][120] Later puzzles provided concept art and alternative cover assets for Portal 2.[121] After about a week following the beginning sale, emails from Newell to various press outlets revealed parts of a picture that, when assembled and decoded, provided part of the lore of the alternative reality game, and other clues.[122] A further update after certain puzzles were solved included Portal-themed updates to each of the games in the Potato Sack, such as complete levels based on Aperture Science for The Ball and Killing Floor.[123] By completing specific tasks in the games, players were awarded a virtual potato that appeared in their steam profile; later it was revealed that those players that earned all 36 potatoes available through the Potato Sack and alternate reality game, about 1800 players total, received the complete Valve game pack through Steam.[124] Based on the hidden messages in the solutions found by those playing the alternate reality game, and a countdown timer that appeared on the fictional Aperture Science website, some postulated that Portal 2 would be released a few days early, even as soon as the morning of April 15, 2011.[125][126][127][128] Instead, at that time, "GLaDOS@home" was launched, a spoof of other distributed computing programs, which encouraged players to play and complete various challenges in the Potato Sack games to release Portal 2 on Steam before the planned April 19, 2011 date, under the pretense of providing enough computational power to "reboot GLaDOS".[129][130] The efforts of those that participated allowed the game to be unlocked on Steam approximately ten hours before the originally planned time.[131]

Overall, the alternate reality game received mixed response from gamers, some praising it as outstanding marketing between Portal 2 and the indie gamers, others considering it a way to force players to buy games they do not want to gain access to Portal 2 earlier.[132][124][133] Pete Davidson of GamePro considered it a "risky marketing move" that relied on Valve's long-standing reputation with the community to build on their trust, as well as a "hugely positive sign of support for indie games" from the company.[132] David Ewalt of Forbes considered the tactic a huge benefit for the indie developers, whose games led Steam sales charts in the weeks leading to Portal 2's release.[134] Ben Kurchera of Ars Technica noted that it was entirely possible to ignore the alternate reality game without any negative effects or losing any potential benefits.[135] Luke Plunkett of Kotaku was more critical, commenting that for most players in North America, having the release only ten hours earlier—occurring overnight for many—would be "business as usual" in that they would not be able to play until the next day; thus, players that purchased and spent time in the Potato Sack games may have simply wasted their money for something they didn't want to gain almost nothing back.[136] Retailers in countries where the disc-based version of the game would have lagged a few days behind the Steam release opted to break their street date to avoid losing sales to the digital downloads.[131][137][138]

The Steam version of the game on Microsoft Windows and MacOS X includes bonus content based on the 2011 film Super 8. The content is a small level inspired by the film constructed within the Source engine.[139]

Reception

Portal 2 was a strong favorite of gaming journalists from closed-door previews at the 2010 E3 convention. The Game Critics Awards, selected by a large number of journalists and critics, awarded Portal 2 the title of Best PC Game and Best Action/Adventure Game,[148] and nominated the game for Best of Show and Best Console Game.[149] IGN named Portal 2 as its Best of E3 for PC, Xbox 360, and PlayStation 3 systems as well as Best Puzzle Game, further nominating the game as Best Overall Game.[150] Gamespy named Portal 2 the Best Overall Game and Best Puzzle Game of E3.[151] Portal 2 has also won the Spike VGA award for "Most Anticipated Game for 2011". PC Gamer awarded Portal 2 a 94 out of 100 and an Editor's Choice award.[152]

On release, Portal 2 received universal praise from reviewers, resulting in a accumulative average score of 95 out of 100 according to review aggregator Metacritic.[153]

Journalists noted that many of the user reviews for Portal 2 on Metacritic evoked negative opinion of the game.[154] These users cited complaints about the game being too short (with some saying it is only four hours long), the existence of paid downloadable content at launch for some versions, and supposed evidence that the game on Microsoft Windows and Mac OS X were ports of the console version. Journalists have defended Valve in these claims, countering that the game's length depends on the amount of immersion the player puts into the game, that the downloadable content is only cosmetic additions for the co-op mode, and that the quality of the graphics on the Windows and Mac version do not suggest a simple console port. Some journalists also identify that the minimal impact of the Potato Sack alternative reality game on the early release of Portal 2 may be influencing the user scores.[155][156][157]

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