Here, I did what I could to fix the ass legs and crotch.
I'd say focus on getting the look right before faffin' about with colors, it can be a bit difficult to learn the art of color reduction and right now your stylization problems are what needs that focus.
also, this is what I meant by squaring the shoulders! (EDIT: I only did them to the left and forward facing sprites) Bringing them up a pixel so it looks like he's gearing up to take a fighting stance. Sort of a held half-shrug! Squared shoulders usually imply anger or brutishness, try to think in terms of body language a lot to get across the point of your character designs better!