When Jake Mazursky gets into the fight at the party while looking for Truelove, he is hit with a glass bottle, and his head begins to bleed. At the end of the fight, there is no blood or any sign that he was hit by the bottle.
When Jake is dunking Truelove's head into the pool, Truelove's dog runs out and starts tugging on Jake's right leg. In the next shot when Jake is being pulled off of Truelove and away from the pool his right leg is now coming out of the pool as he is being dragged away.
When the Alma, Julie, and Zack are in the pool, Julie ties the tie round his eyes. It's tied, then tied in a bow, then hanging loose, then in a bow, then loose again.
Keith Stratton is only around for a day, but he changes his clothes several times.
The air conditioning unit in the "bust scene" wasn't released until 2006.
The morning of Zack Mazursky's kidnapping is stated as Friday, November 6, 1999. November 6, 1999 was actually a Saturday.
Near the end of the movie, when Johnny is in the red truck going to his Dad's house, the front of the red truck has a New Mexico license plate on it. New Mexico only uses one license plate, on the back of the vehicle.
In the end of the film, Olivia Mazursky is being interviewed at Camarillo State Hospital. That hospital closed in June of 1997 (and is now Cal State University Channel Islands). Seeing as her son was murdered in 1999, there is no way she could have been in Camarillo.
When Jake goes home to see what's going on with his younger brother, he goes straight to the fridge, grabs a beer and twists the top off. A moment later, the beer is a Heineken, which requires a bottle opener to open. Old-fashioned bottle tops can be twisted off, though it's more difficult (and painful) than using a bottle opener.
During the threesome in the pool, Alma jumps a little bit out of the water, exposing her left breast for an instant. A patch is visible, covering her nipple.
Twice in the film, two characters are playing on a Xbox console, although the screen shows only one player currently playing. If two people were playing, the screen would be divided in half.
At the party, when Julie and Zack go in the refrigerator, Julie grabs 2 beers and tilts them completely upside-down, but nothing comes out.
After Elvis introduces himself to Zack and then steps out of the motel room to talk to Frankie outside at the 1:28:36 mark, you can see Elvis coming out of the room with a door to an adjoining room immediately to his left. Zack was seen watching TV at the 1:25:23 mark where the door to the "adjoining room" is and yet there is a wall in that room where the door should be.
Characters play Xbox, despite the fact that it was first sold in 2001.
Characters play the game F.E.A.R., which was released in 2005.
Towards the end of the movie, when Trulove and his girlfriend are "trying" to have sex, the song "Slither" by tech N9ne is playing, and the video is on television. The song appeared on the album "Absolute Power," which was released in 2002.
The film is set in 1999, but several background vehicles are newer than that, including a 2001 Volvo V70, 2005 Chrysler Town and Country, 2001 GMC Yukon Denali, and 2003 Toyota Sequoia.
Johnny Truelove's house has a Pioneer plasma TV. The first plasma display for consumer use was sold a month after Zach's murder.
Magic Hat beer appears in several different scenes. The film takes place in California, but Magic Hat is only sold in the Northeastern US.