TiagoSC on the NES Dev forums brought an early version of Sonic to Super Nintendo. Some have said Sega does what Nintendon't but apparently it's more like NintenDOES! Digital Foundry has a great break down video of it and some of the tradeoffs TiagoSC made. The SNES version is cut down visually a bit but I appreciate the SNES soundchip for Sonic a bit more than the original.

http://forums.nesdev.com/viewtopic.php?f=12&t=20638