Despite the technical points people previously mentioned, I really love the art! I don't know why, it just works as it is. It tells a story, it's dynamic. It's simple but it's efficient! And having your menu and game area somewhat "inside" the environment was a really nice touch.
Obviously a rhythm game is very complex to make. I would raise the same concerns with the notes getting out of sync and the gameplay being a bit too simple, but it takes a lot of time (and playtest data) to get those just right. You did good considering!
Keep on making games! See you at the next jam!
P.S. thanks for the WebGL build!