Tails' Adventure

Tails Adventure has just enough mainstream elements to fit into the Sonic franchise, but really branched out from the original mechanics. Tails moves a lot slower (so levels have more verticality and platforming), and all manner of gameplay and progression revolves around collecting and using items (does that sound familiar, players of Sonic Adventure?). The game doesn't have SRAM, but it does have a password system. As such, it had design space for a somewhat long game. Progression is not as linear as in the rest of the Sonic franchise; Some levels need to be replayed to fully clear them, and there are a small handful of places where players can choose alternate paths. I don't remember how I did it as a kid, but there's even a way to skip to caron forest early to get items there (possibly a bug). Maybe it's just me being a Tails fanboy, but the sprites for Tails are adorable in this game. He celebrates when he finds items, he forages when he is idle, his attentive expression when crouching and using the wrench is the essence of kawaii... I want to pat the top of his little head. Even the credits movie was adorable. The fact that this game didn't show up on the Gamegear Micro(s) is the reason why I didn't even consider buying them. It's a must-have.