Absolutely adored this game! The effects, map, and characters models all reminded me of old sonic and mario games.
In terms of suggestions, however, I think you should fix the camera since it kept moving downwards whenever I moved forward. Also, I know you're going for a "retro" kind of style but that doesn't always mean everything has to be crazy saturated. It kinda hurt my eyes a bit lmao. Another issue I had was where an enemy attacks me continuously to the point where I couldn't even dodge or attack, just instantly died while being knock-backed to oblivion. Personally, I would make it so enemies have a small delay after attacking, giving the player a window to at least do something.
Overall, this game was peak CINEMA. Loved EVERY minute of it!!!!