Jack's eyes are asymmetrical, but they don't look like they're going in opposite directions in the comic, as they do here. Some approximation of similarity in the eyes would be good.
I was attempting to insinuate that he looked to thin, but upon further examination, it's not so much that he's too thin, but that his arm is too wide.
I still think that you made WV look too dirty. the level of grime matches this appearance: [link] But when making a smaller sprite, chances are you're better off not using the less common, more detailed version to scale down.
But again, they all look great, those are minor gripes. Just trying to help, is all.