The ambient light definitely seems to be hurting. I don't see why you'd need/use ambient light in a game, unless it's always present.
The character looks like a cardboard cut out. You do a lot of shading that goes light-dark-light around the sides, and it's really messing things up.
Also, in some parts, I see what sort of looks like pillowshading, in a way. Even if you removed the ambient light, say, on the face, you would still have dark on both sides of the face, while it is light in the middle.
Fix up your shading/lighting, and try to give it some volume.
