Sonic X'treme [cancelled game]

It was originally developed by Sega for the Mega Drive/Genesis but was moved to the Sega 32X and eventually to the Sega Saturn and intended to be released around Halloween of 1996, but after many problems and a long hiatus of development hell, it was finally cancelled in 1997. Had it been finished, it would have been the first fully 3D Sonic game and the first original Sonic title developed for the Sega Saturn. Because the game was cancelled, Sega released a port of Sonic 3D Blast for the Saturn in 1996.