Bioware
Bioware is the company behind popular games such as "Dragon Age: Origins" and "Mass Effect 2." Bioware is a respected developer, with its "Neverwinter Nights" title ranking No. 9 in GameState's "Top Ten Games of All Time" as of March 2010.
Lionhead Studios
Lionhead Studios is widely known for creating the "Fable" series of games. "Fable II" was an Xbox exclusive, and "Fable III" makes use of Microsoft's top-secret Project Natal technology.
Bethesda Softworks
Besthesda Softworks is the company that is responsible for the "Fallout" and "Elder Scrolls" franchises. "Fallout 3" carries the distinction of being named 2008's "Game of the Year" by the Game Critics Awards.
Square Enix
Square Enix maintains the "Final Fantasy" franchise and focuses exclusively on RPG titles. Though the company has shipped more than 96 million "Final Fantasy" games as of 2010, they were not available on Xbox until 2010's "Final Fantasy XIII."