In the mission "Aftermath", if you get out of the back of the Chinook and turn left, there is a playground directly ahead. As you approach the playground, you will hear the haunting sounds of children playing.
In the flashback mission Captain Price indicates that the mission is a decade (10 years) after the Chernobyl disaster, this would mean that the flashback mission occurred in 1996 as the Chernobyl disaster was in 1986. The flashback mission is said to be 15 years in the past, this would mean that the year the game is set is 2011.
Despite its title, this is actually the 8th game in the "Call of Duty" series.
The playable character 'Soap' MacTavish had no voice actor until Call of Duty: Modern Warfare 2.
Many of the minor soldier characters have the last names of the game's programmers.