Dropped a color, I think.
Changed the grays to a greenish tint so they could be used to help shade those barrels or thrusters.
Touched up some other areas to show how the colors could be used to help AA.
There are several reasons to avoid dithering. Really, it only works well on larger sprites, backgrounds, etc. I wouldn't use it on a sprite any smaller than this one. Also, animation is deemed just about impossible. Animated dithered sprites tend to look horrid.