He could use a little more shading, mainly on the arms, legs, pants, and face. Color choice could be better; his skin has a rather yellowish tinge, don't know if that's what you're looking for. His neck is a little long and too gray. The handle of the weapon looks pillow shaded, and the red design could be improved. And the highlights on his blue shoulder pads(?), mainly the bottom area, are too bright. You could also work on lineart-- I'm talking about the fingers, its shape could use some work.
All in all, it's quite a decent sprite. Just work on some little things like I mentioned.