Very nice game, impressive scope for the length of the jam! I was impressed by the graphics, very consistently high-quality stuff with nothing that stood out as particularly bad at all. Your animations were especially nice! Great idle, jump and attacks for the main character, and the quality extends to every character and environment design in the game!
The levels got a little repetitive in the types of movement there was to do; Most of the moment-to-moment obstacles were either dash to a platform, fight (or run past in my case) an enemy, dodge a spinning axe, or jump a gap, with each screen being an ever-so-slight variation of the same few scenarios. Tough to say what could be done here; Feels like a quantity over quality issue, so perhaps focus on a tighter level design, introduce a unique movement mechanic of some sort that allows for more unique scenarios, or ensure there are less identical scenarios in the levels in general. It's a big challenge for a game jam for sure, and what is there is still perfectly serviceable.
It was somewhat strange flow-wise to be taken back to the main menu after each boss fight, instead of just moving on to the next level.
The last two boss fights in particular were kind of tedious, with them all feeling like they all needed to be cheesed in some way. Not too big a complaint there considering the fact that your game even had three separate bosses, with varied attacks and designs for each one! I think it's just something that requires more playtesting and time to develop workarounds to those issues.
Overall, your game is a a fun, well-polished project with a clean, effective visual style and an impressive amount of unique content for the time it was developed in. Great work!