Sega is continuing their series of 3D enhanced games with Altered Beast. This is the Genesis version and not the arcade version so it won’t have the silly ending sequence with a dude taking off the beast costume in front of a director’s clapboard.
3D Altered Beast supports local co-op if both players own the game and has a new "whimsical transformation" mode too. Sega hasn’t said what actually happens in the bonus mode.
M2 added the usual features, stereoscopic 3D with options for depth or zoom, button remapping, a tube TV display mode, and the ability to play the Japanese ROM or the international release. The 3D effects in 3D Sonic the Hedgehog were pretty weak so I’m more hesitant about picking this up since it’s another Genesis port. 3D Altered Beast comes out in Japan on May 29 as a 600 yen ($6) eShop download.