Great start!
I love the look of the game as well.
On the negative side, I felt like I could just tap as fast as I could and do just as good as if I was tapping to the rhythm. The game would probably benefit from punishing the player more for missing notes or tapping as fast as possible.
Also the score seemed unnecessary. I couldn't tell when I was doing "good" or "bad"
I love to see this kind of game on ios!
I'm excited to see what else they can make!