Its highly detailed, but remember hero characters are usually atleast 8 - 9 heads high, luckily its not reality so you dont need to give him a standard frame. I think his rib cage is the wrong shape and his hips need to be more prominant, you have build his bicepts but he really needs the classical proportions to compliment the proportions your trying to give him.

Check out christopher harts heroes and vilans book on proportions for this kind of thing, its awesome. That and hograths figrue drawing books show super pronounced muscles correctly.

The anatomy just seems off some what, when anatomy is so exhadurated and the muscles so pronounced, make sure that the ligiments are flowing in the right direction and the skin is bulged in the right places. Muscles are not a surface detail.

Genearally this is a strong piece and is an extremley challenging subject that many sculptors would shy from, keep it up.