Well, there's really not much more that I can say that hasn't already been covered in your comments below. The hot spot of light on the right is a bit much for me, but I'm sure you made that conscious decision and I can't argue with that. The subject of the image is perfect for the challenge and, alien or not, it definitely does depict motion.
This would probably be effective in B/W as well, as you might lose some of the prism effect around the edge of the spinning head. Some higher contrast, either in color or B/W would also bring the belt (?) out more from the background.
Great depth of field, though. I think it was very well done.