Nice, if you would take a bit more time this photo could be much better. Hiding your face, well, at least you could show the eyes. That's ok. Seems like you wanted to share the whole frame with your shadow, if so I wish your shadow would be a bit darker. A frame would do fine with this posing also. Overall is a good photo :)
Very shapely - both of them. :) Wished ya wouldn't have hid the face, but maybe you're on the run from the law or from the mob or something. Yeah that's probably it. :)
I really like your take on the challenge, I think if you held the guitar though, like your were playing it, so we could see your face it would be a better portrait. However you have great composition and lighting. Nice work.