Retro Studios, Inc. is an American video game developer and subsidiary of Nintendo based in Austin, Texas. The studio is best known for its work on the Metroid Prime and Donkey Kong Country series, and has contributed to several other Nintendo-developed projects, such as Mario Kart 7. Retro was founded on September 21, 1998, as an alliance between Nintendo and Iguana Entertainment founder Jeff Spangenberg, hoping to create games for the upcoming GameCube aiming at an older demographic. The company began work on four games, all of which were canceled once Retro focused their resources on Metroid Prime, the first Metroid game developed outside Japan. The success of Metroid Prime led Retro to work on three sequels, and later to become involved with reviving the Donkey Kong series with Donkey Kong Country Returns.