Very nice music and rhythm overall.
The thing I would like to see improved is the fact that the different arrow key visuals look the same to each other, just different orientation, so it's very hard to immediately knows what keys to press. You sort have to pause and interpret them, which is much slower and prone to error. Rhythm games like Guitar Hero have their buttons color-coded for example, so the monkey brain can process it much faster :) I hope this is some small suggestion for the next version of your game.