Majin Buu much?
Oh how constructive that was.
Anyway, I'm not a big fan of the legs for some reason. The one closest to the viewer looks like it's bending like rubber, especially in the transparent version, which is probably caused by the low contrast in the crotch. The sharp, slightly blocky angles of the pose look a bit awkward to me. It's not all that big of a deal, but I usually think of aliens as being more organic and thus having more natural and relaxed poses. Lastly, his right (viewer left) forearm seems too short compared to his upper arm. Unless it's supposed to be at a slight angle which would incorporate foreshortening, if that's the case then it's really hard to see any signs of it. You got the foreshortening of the other hand down pretty well, although it's hard to see for me since there's not much contrast there. A highlight along his knuckles might help that. So in short, I'm not a fan of the stiff angles and (lack of) contrast in some places (which could just be me).
