I feel your pain. ;p I'm not really an artist so all I can give you is my general impressions. I think it looks pretty good though.
I'm not sure I dig the eyes, they kinda look like sunglasses when I zoom out. Color choices make him kinda bland, like the green hat - the top of his hair really blends into it. There's something I don't dig about him not really having a neck, but with the height of the sprite your going for I dunno what you could do.
How's that for unhelpful. ;p