Perhaps inspired by Super Mario's Wacky Worlds, some American designers at Sega back in the day figured hey, maybe we could make a Sonic game. Here's a never-before-seen video of their efforts. It's an interesting take, to say the least – what would happen if Sonic, instead of running really fast, plodded slowly through trap-filled levels and could throw rings at things to kill them? Actually this looks like a significantly better idea than the actual Sonic games, so of course it was cancelled.
(hat tip: FortNinety)
