The trunk of the tree isn't shadowed by the leaves... and it should be, in my opinion.
That's pretty awesome, though.
The grips I found are that his skins could make more contrast to reflex the BG's style and that what seems to be his shadow is not angled rightly if compared to ther est of the shadows AND the sprite itself. But these are so tiny near the rest of the piece.
Gotta love the leaves =D