I agree with Gil, the jagged outlines are detrimental. Other than the issues already mentioned/addressed, i think the quadriceps (vastus medialis) on the leg to the left is exagerated too much. The calf muscle (gastrocnemius) of the leg on right is also too exagerated (when i say exagerated, i mean style-disrupting exageration).
Also, the arm on the left looks broken in several places: below the deltoid, and midway through the forearm where muscle and bone meet.
Proportion wise, he looks very tall, somewhat around 2 meters high, and current muscle mass is both odd for such a tall frame, and distributed unevenly throughout his body, some places with huge bulk while others very slim. It may be style choice, but it's a disfunctional style.
The perspective seems to be inconsistant, from the waist up is different than downward from there, and changes a few times on his legs, knees, feet.
Gil addresses a left ankle brokeness issue on his edit.
Other than that, i like the suit design, the face is very nicely done, the dynamic pose, and the palette on the skin and blue parts of the suit (the brown parts look kind of washed out and monotone in comparison).