Main game
2.37 average rating based on 38 ratings

Good gravy, this game is a mess.
It's not a complete mess. There's good music, great use of color, fun new characters and bosses, and technically impressive special stages (at least compared to the Genesis).
But the core mechanic of tethering two characters together is just totally unappealing to me. Look, I know it has its defenders, and I'm sure it's eventually possible to achieve mastery of it, but it's such a drag (figuratively and literally) to get to that point. It just feels so wrong for basic movement in a Sonic game to feel this baffling... I didn't like the team mechanics in Sonic Advance 3 or Sonic Heroes either, but at least those games don't make you feel like you've repeatedly reached the end of your leash. Even when I grew more confident with movement it didn't feel like I'd achieved mastery of anything, it just felt like I'd learned how to break the game's wonky physics.

The levels don't help matters either. I've always preferred the leaner "two acts per zone" structure of Sonic 2 and after, but five acts gets ridiculous. Even stranger is how you play these acts in a random order, completely throwing out …

Good gravy, this game is a mess.
It's not a complete mess. There's good music, great use of color, fun new characters and bosses, and technically impressive special stages (at least compared to the Genesis).
But the core mechanic of tethering two characters together is just totally unappealing to me. Look, I know it has its defenders, and I'm sure it's eventually possible to achieve mastery of it, but it's such a drag (figuratively and literally) to get to that point. It just feels so wrong for basic movement in a Sonic game to feel this baffling... I didn't like the team mechanics in Sonic Advance 3 or Sonic Heroes either, but at least those games don't make you feel like you've repeatedly reached the end of your leash. Even when I grew more confident with movement it didn't feel like I'd achieved mastery of anything, it just felt like I'd learned how to break the game's wonky physics.

The levels don't help matters either. I've always preferred the leaner "two acts per zone" structure of Sonic 2 and after, but five acts gets ridiculous. Even stranger is how you play these acts in a random order, completely throwing out any sense of pacing or variety. And the acts themselves are as sprawling and non-linear as Sonic CD, but with a far weaker sense of design.
I'm glad I finally resorted to cheats and save states to casually finish a playthrough, because it's fun to experience firsthand some of the stronger ideas (many of which fans of Sonic Mania and its Encore DLC might recognize). It's just a shame those elements are built on such a counter-intuitive foundation.
Used Debug menu to just play Act 5's + Final Boss
Side Note: My god is the worst Sonic 2D game I've played, even beneath Sonic 4 to me. The rubberband mechanics usually works against you. The repetitive level design is very poor with rarely any enemies and sense of direction, and the bosses are mostly forgettable. The only positives are that the graphics and music is neat, and that the special stages is an interesting take.
Also Charmy just breaks the game.