The head looks a little awkward in my opinion, compared to the body. The lines could use some work too; the black lines on the head and the right side of its body look a bit rough, they could be shaded and AA'd since the rest of the outlines appear to be. The background should be transparent or at least in a different color; that way, you can see your pixel art's look better and find possible mistakes to fix ;) I hope this helps.
gracias poe el consejo