Note that game credits sequences are sometimes just a list of who works at the company at the time of release, and not an actual reflection of who worked on the game.
This has resulted in a few problems where people get their name stripped off of a game they worked hard on but left the company prior to release etc. Also people may appear on the credits that were in fact in a different department on a different team and never touched the game.
From what I hear this is a problem in the movie industry as well. When you have a huge project that requires the work of hundreds of people spread across multiple years, and possibly multiple sub-contracting specialty companies, there's a lot of cracks for names to fall through.
