Galactus 'pixel-art' CnC needed

[Hoeloe]

You need to select a definite lightsource. Find where the light is coming from first before trying to shade. Most of this sprite suggests a lightsoure from the front, but the face section of the helmet suggests otherwise. It should be easier to shade the helmet once you've worked out where the light is. Be careful not to just pillow shade it though. From the angle the sprite is at, it seems that very little shading is needed on top of the helmet, if any at all, and should probably be focussed around the side of the top section to try and convey the shape.

Also, you're using far too many colours for the shadows. I can count four on the top of the helmet, but only two are really visible. Another thing is that it looks as though you are just decreasing luminosity to get your shades. While this does work, you should try hue-shifting a little.