Wonderful effect! The lighting is very nice, and I definitely like the idea. But...
There's a red line I think that runs under his eye. Until you open the full sized image, it makes it look almost like his eye is open when it's meant to be closed.
He almost looks like he's sitting a bit far from the piano, though I'm not sure how you would move him much closer while keeping the subject visually separate from the piano. Is the piano a bit short maybe?
I definitely like his posture.
The piano itself looks a bit flat or two-dimensional. You don't get a good feeling of perspective. The lid could have been drawn a bit differently with respect to the horizon and camera angle (the top of the lid should be wider I think to appear closer to the camera, and with respect to the angle of the lid). The rest could be corrected through lighting and shading, perhaps more shine where the middle part starts to curve?
Other than that, I really like this piece.