Nice use of shading on the arms and legs to push the animation. :)

Very nice.

I assume your choice is a matter of personal style and I love it, but if you want to try that and haven't yet, you can try to make a more "skully" face by modifing two pixels. (Coloring with the darkest color the one just under the eyes and between them, and the other one is the pixel justbelow the first, in a bone color.

Just a proposal, not a crit, I really like it as it is.