I feel like this game is off to a pretty solid start, and blitzing around in this super-low poly enviroment was really fun even isolated from the traditional Sonic level design tropes, but there are ways I think Project 32X could be improved.
Handling: I do understand that for what P32X is going for, more natural handling akin to the Adventure games is a no-go. That being said, if you're going to go for more snappy movement, I'd recommend giving Sonic a run and/or break button so you can more naturally alternate between speed and smooth platforming control like in Lost World. Also, maybe add a raycast so Sonic can go down slopes more smoothly.
Level Design: I think that act one was the weakest level of the game, primarilly because the camera is not well-suited to the player walking towards it. (something the PS1 Crash Bandicoot games struggled with too, for the record) I think you should have more levels like the second one, where you're primarilly running from/along the camera, and where obtaining collectibles is a matter of path selection.
Conveyance: I also feel that while the animation on Sonic is off to a pretty good start, he's missing an animation for taking a hit. Aside from the bounce-back, there's practically no audiovisual conveyance that he took damage. And on that note, it's too easy to get flung off bottomless pits. I'd either change the level design or give Sonic the recovery jump from the Adventure games.
It's still a very commendable effort, so keep going. I look forward to seeing how P32X evolves at future SAGE events.