Dwayne Johnson was originally supposed to play James and Ryan Reynolds was originally supposed to play Ben.
When Ice Cube is talking in the conference room about the 126 experience, he says "today was a good day." He is actually quoting one of his popular songs titled "It Was A Good Day."
WILHELM SCREAM: When Angela stops Ben from playing the shooter game, and his character gets shot.
When talking about the criminal Omar, Ben asks if he has a scar on his face. This is most likely a reference to Omar Little, a popular criminal from the HBO show The Wire (2002), who had a scar across his face.