Oeh nice colors! You seem to have smudged a bit over his face, if you would keep the face clear from smudging the render would come out more and you would have better depth!
Nice colors, the background is a bit to empty. I like the smudging over his shirt but not on his cheek and hair.
If simple is what you were going for then you got it, but if not try adding a few more effects. Looks nice imo.