Your proportions are okay. Refine the linework or loosen up the overall drawing, you can't have that many lines defining the outline AND a stiff pose AND expect it to have much impact.

I like what you tried with the background but pick up a graphic design book and find an example where they use bold colour but keep it in line with composition/type/less colour. I like that there's type in there that isn't in the predictable bottom corners.

Check your anatomy, the muscle bulges are off.

I like the character design, those colours look yum. C: Post more stuff (or crit to my thread, haha).