I've detected a bug.
The only problem with this is that the guitar is the most awkward sounding thing coming from this.
I can't hold a note and so it's just a jumble of quick notes happening over and over and over to where it sounds very annoying. No matter which way I position the notes it always comes out quick and not having the effect I hoped it would.
If you make another, could you add a feature that allows the maker to stretch the notes or alter the frequency of the note to where it isn't just the quick strum of guitar?
I can tell where I place my notes, that's an improvement, but the keyboard pretty much had the same flaw as the guitar.
To get to the bug.
When I was doing some experimentation with drums and guitar, the screen pretty much just ran down the bottom of the window, and I had to restart the whole thing since the screen went blank. The back button didn't work when I went to complex mode either. (Is this just me?)
After a while it can get very annoying, and the pacing seems to differ inbetween notes, making it go off tune quite a few times. Call me a nitpicker.
Aside from the criticism, I present to you a 7/10. Work on it and polish it to where it's all neat and tidy, work on pacing of notes, add more freedom to the userspace...there's quite a few things to work on, but don't give up! It's a very good concept!