Starting off with some issues first, the music was a bit too loud in my opinion so you could add a volume slider. The menu size can also be reduced a bit (this is just my opinion). In the levels, there are some collision issues.
Still for the most part, the music was actually quite good, the visuals are pretty nice (although would obviously be better with a bit more polish), and the collecting gems and running away from chaos enemies (and eventually shooting them) are quite nice. Overall, the game is genuinely pretty nice!