First I must say, a very wonderful piece. The shading and the light in the background are beautifully done. Now onto the critique.
The man in the foreground, his arm kind of melts into his body with no dividing line or way to tell them apart. That's the main thing that's bugging me, which means this is a really good picture.
I believe the folds of the clothes could be a bit more "dynamic" if you know what I mean. There could probably me a few more too. Looking at my shirt now, I either have a very wrinkled shirt, or he has a stiffly ironed one.
The hair too, I think could have more of a sheen. Feel free to disregard that though, it may be the result of watching lots of anime.
Last, a question: what is that bar at the bottom of the picture supposed to be? Right now, I'm imagining it as some sort of rail, but it'd be nice to know what it is.