To the left of the arm looks weird. Looks like you tried to cover a part of the render up with a soft brush. Take out the bottom border. The colors are kind of crazy, and like others were saying, needs some depth. Try to sharpen some places up, or blurring others. Or use the dodge and burn tools to try and get some depth in places.
Depth and some improvement on the lighting would be nice. I appreciate your smudging, nice work, the compo is nice as well.
Great start I would say just keeping adding to it ;] And like I always say put a border around that thing =P
