sweet.
i like how the reward of getting good at the game is being able to hear the song with no "errr" or "clinks", similar to guitar hero. I also like how you added simple and complex parts, so that at least everyone can hear a little of the song, while working to get better on the hard parts. the fluctuating wave effect and different instruments were nice touches.
an obvious suggestion would be to have more songs, some easy, some hard, but I get that time was short. well done, otherwise!