Very nice and distinctive visual style. I'd suggest putting a few screenshots up on your itch page; I think they would get you some more attention/ratings, since the game looks visually interesting,
I enjoyed the combat, though I should mention I'm already familiar with Osu mechanics; I could see it being challenging to people who aren't, since it seems like it only takes one bad combat to kill you.
Overall a solid entry; I didn't (knowingly) hit any bugs, and once I understood the combat I was able to play straight through to completion. Nicely done!