It looks amazing, I really like the reflections. I think the only thing that could use some work is his hand, something with the fingers Here's my work http://guang2222.deviantart.com/ juanphotoshop@yahoo.co.uk
That shininess is really impressive, is it all just 2D drawing and painting? I wouldn't mind knowing how you did that because I'm going to be doing a lot of sci-fi stuff. The only complaints I'd have is that the colours in the environments are bit dull.
It is sometimes the case that even though you've painted exactly what was in the reference image, it doesn't look right in your painting. That hand definitely needs to be bigger. Great work overall though, like everyone said, the shininess is very impressive. http://www.artfulscruff.co.uk | deviantart