Co-op has been a staple feature of many Sonic games for decades now. These examples are the best of the bunch.

Sonic Galactic is a fan game reminiscent of Sonic Mania, appealing to fans of pixel art and classic Sonic gameplay. The game features new playable characters Fang the Sniper and Tunnel the Mole ...

Sonic Mania was developed by PagodaWest Games and ... solve various puzzles, and run through Cyber Space levels modeled after the levels from past Sonic titles in an effort to save his friends ...