I love the composition you have created and the overall "feeling", but there are some things that bring the quality down in my opinion. First, overall sharpness is lacking (probably due to the 1/15 shutter speed), second is the dark face so you can't see any detail in his expression, and third is the sightly slanted bright window panes? that are in the background. They are distracting for me. I'm thinking that you could have shot at highest ISO to get your shutter speed up a little. Higher noise would not have hurt this photo at all. Anyway, these are just my opinions.