How do we know? It's all thanks to a custom Sega Genesis cartridge. IGN received a Sonic the Hedgehog 3 film mailer this week that includes a Sega Genesis cartridge that's actually playable.

They are effectively programmable hardware devices, capable of creating specific digital circuits and custom logic for ... [nukeykt] has been developing a Sega Genesis clone using them, with ...

The great console wars of the early- to mid-90's was waged between two titans of the industry: Sega and Nintendo. In Nintendo's corner was the Super Nintendo Entertainment System, while Sega hit back ...

Those kits include a working Sega Genesis cartridge, complete with custom box art. The cartridge has a minigame featuring Sonic and Shadow, along with character art and posters in pixelated glory.