Also, the gray strips, they look like just gray strips, don't really flow with it I think. So maybe if you put them on overlay or added a glossy shine to it, it would fit in just fine
I think that blue dot is a little out of place, might just be me though.
A little gloss on the eyes would make it more realistic.
I agree with some of what beta said about the grey strips, they stand out too much, dont match the rest of the head and makes it look flat. a simple and soft shadow would go a long way
the metal texture looks a bit low res/quality, doesnt gel nicely with the textures lines.
otherwise it looks fine, a full set would be worthwhile