The art style catches the eye immediately, very unique but fun! Music is great and the controls feel simple enough, if a bit hard to nail down.
Bosses had a wide range of difficulty which is expected, but it would be best to get some indication of what order might be best to approach them, for instance the turtle boss was easy to do first try while the plant took many attempts. Only specific issues I had was how the plant boss' particles (the ones that show where the roots will sprout) also hurt the player which defeats their purpose, and that the moth boss' projectiles can hurt you on their way up, which felt a bit cheap. The game could also benefit from having some amount of i-frames since some bosses can really stack hits on you one right after another under the right conditions.
Other than that though, it's a good challenge and plenty of fun! I couldn't beat the final boss yet but I feel compelled to keep trying since I'm having a lot of fun (I also massively appreciate the fact that the game saves, since that final boss might take more than one session). Well done!