This looks great! Level design seems to be a lot better than your average Sonic fan game. I like the custom sprites, like Sonic having his hand closed when in max speed (feels more like classic Sonic), bent spin dash and insta-shield from Advance, the signpost a mix of Sonic 1 and 2. The bosses made of multiple pieces is very reminiscent of the 16-bit era in general and look very cool. The new levels feel unique even when they repeat pre-existing tropes, like snow stages, and some of them don't seem to fit in old tropes at all. This in particular makes me wish it was an official game. I also like how you mash old gimmicks together to create new gimmicks, instead simply of using old ones with new graphics. This is the right approach, it's familiar and new at the same time. The only constructive criticism I can give is that the main menu feels a bit slow and you can't see what the options are without cycling through them (some people might not even notice there are other options, since they're hidden). This seems to be a minor nitpick, but you have to consider that the average player will see that screen a lot and it is the first impression of the game, even before the gameplay itself. So the least friction there, the better.