Semont is right. I've tried to make old bronze mechanism with scratches and rust, so the dithering helps me in that.
I disagree with MaRom, the sphere centurions are old bronze/brass robots and of couse they would lose their lustre over time. I think the dithering and colour choice reflects some of that.
That isn't exactly informative. What about the colors is bad? What about the dithering is bad. Going around calling things 'bad' without supporting your opinion is just antagonistic, not helpful.
Ooh, my favorite enemy design from Morrowind :)
It's a bit hard to see where all 12 colours went to, though- you could have either used more shades to make it less harsh, or reduced the color count altogether :)
Maybe adding a contrasting, secondary light source (softer blue or green light from the right, for example?) would be a good idea, to add contrast to the monochrome orange palette?
Still, it has good shading and form, and it's a very accurate depiction of the sphere centurion :)