The third one has a really nice animation.
The first one, however, has too much black in it, try using some dark color but not black, especially on the border of the light in the center : )
The 4th looks like he's fapping (sorry to put it like that), you could try alternating the left legs and right legs movement, like you did with the 3rd!
I'd do a quick edit but I'm at work, so..