Looks like a really cool concept! Unfortunately I could not figure out how to play the guitar as there are no controls specified in game and on the game page. :(
You use the arrow keys to play the guitar. There's a graphic that appears in game meant to relay this but admittedly it's somewhat vague/easy to miss. I'll actually add the controls to the game page though and make it more obvious in future versions. Thanks! I loved your submission by the way.