the breathing is a bit overdone. specially for the abs. with that mass of muscles, he shouldn't inflate like a meat ballon doesn't him? or at least, if this is suposed to be an idle stance, and he remains calm... his abs doesn't need to inflate that way to breathe. i know that the shoulder rising thing is, somehow, used to boost the power stance look, but they are overdone too. a more subtle movement would probably look more natural and credible, without loosing the idea of the figther sprite.

the anatomy looks quite good at first glance. only a few jaggynes that needs to be cleaned

if references were used, would be a good idea to post them, in order to make comparisions and c+c much easier.

He looks flattened a bit. If you can stretch him up a bit.