Really love rhythm games, and conceptually I think this was really really cool.
I think the lack of visual/audio feedback when you hit arrows correctly really hurts the feel of the game, it's hard to feel together with the song without any feedback. I also think the lack of a fail state in the game beyond just a low score removes any penalty that running into the arrows has. Being able to move up and down would also help with dodging, there's a couple patterns that feel really rough to dodge.
The art is really charming and the remixes are great, I'd love to see you guys take this and make something much bigger out of it. Really enjoyed playing it, though :)