wow, that sculpt is amazing, I used the same base figure to make this character before, but do any of his joints still work? He looks like a statue now.

The legs still move. Most of my customs are effectively statues because I like to cover up seams.

Your version is awesome! I see that you gave him the correct number of fingers. I think your boots turned out better too, maybe I would have had an easier time going for that look. The weird thing about Robotnik's boots is that the V-Shaped cut in the boot shaft is always facing the camera in the show. They're like Mickey Mouse's ears.