This is really awesome, simple and fun. But like ghettoleelewis said it would be fun with more octaves and options, would it be possible to add like a "pro" mode or something? Like it starts upp like it is now and then you can select in game if you want those extra options or not. Or you could just upload a "pro" version in a separate game (does seem a little unnecessary thou)
Still definetly a 5 imo.