I thought this would be kind of cool...I had some flash games similar to this, where you draw on a grid and it plays back as music. Technically, this app meets all those standards. What really irked me was the fact that if you wanted do something more complex, this will force you to purchase several other in-game apps just to have a marginally functional composer and player. Even then, the in-game purchases can't help the buggy interface where most of the buttons do not function, have no names.
So anyways, just don't bother with this unless you are willing to shell out a significant amout of money