Idea: Metroid NFL

Before there was Metroid Prime, Retro Studios hadn't had a bona fide hit, and several of the studio's games were cancelled before seeing the light of day. One such title was this unnamed American football game, recently featured by prominent site Unseen64.

The animation shown below is undoubtedly impressive, particularly considering this game was intended for release on GameCube. Ultimately the project was cancelled in 2001 shortly after Nintendo granted Retro the licence for Metroid, and the rest is history.

[source unseen64.net]