The problem was that they were the wrong shape and for some reason it took me forever to realize it. Thanks, though! I hope to animate it again when I'm done, but I dunno how well it'll work out.
All of the metal shading is very preliminary and will probably go away, so yeah, I know it doesn't look right. ;(
Oh right, zedeem, I was gonna comment on your stuff. I dig the first one; very cool stylistically. I might try to streamline the AA a bit, though, although I zoomed in on it and can't quite figure out what's bugging me about it, so I dunno how helpful that is. The second one is cool; I think I remember seeing it on PJ, actually. Try making the planet bluer to match the rest of the stuff and adding more hue variation in the palette, like slanting the darkest shades towards purple or something. And for the third one, I recommend trying to avoid dithering as much as possible in general. Using solid colors with AA tends to look much cleaner and nicer than dithering unless you really, really know what you're doing with it.
Edit:
Blech, still not satisfied with the highlights here.