Sonic Jam 6

Sonic Jam 6 (aka Super 1998 Sonic 6) is an unofficial Sonic the Hedgehog platformer released in 1998 for the Mega Drive, but only in Taiwan. It was made by Gamtec, the same company behind Super Mario 2 1998, and is actually just a hacked version of that game with stolen Super Mario All-Stars graphics.

The gameplay is identical to the original Super Mario Bros., but with Sonic as the main character. Without a power-up, he’s red, but turns blue after grabbing a Super Mushroom. The title screen and menus were altered to feature Sonic, though some leftover Mario elements—like his face in bonus areas—still appear.