Too Difficult, and a Little Dull
You had a good idea in mind, but the game itself was not very entertaining. I would have liked it a bit more if you didn't have "Elevator Music"; after all, that's the LAST thing anyone wants to listen to. No offense to you or the artist that created that song.
Also, the games in "Sheet Music" were really hard, and I only passed one of the four games. I agree with GameKitten- this game is not very laptop friendly.
But your idea shouldn't go to waste. If you ever plan on making more games like this, try to make it laptop friendly (as in, not involving number key bashing) AND please, PLEASE don't put any elevator music. It bores people to tears.