it's usually a bad idea to do linework on the interior of a sprite in black, it's so dark that the contrast is usually (as is the case here) too strong for the surrounding colors. what are the things hanging down on the side of the crown? do you have a reference picture of the crown? I don't know that dithering is helping here. the darkest skin tone seems too green. bottom of the head is a bit too flat, maybe define his chin a little, keeping the shape of a human jawbone in mind? why is this nose seen from the side? In general it's just a bit small and simple to warrant its own spot in the gallery, have you considered making a body for it?