i love the colors you chose to color the stomach area. i think his facial features can use a little more detail though.
but overall, some seriously good stuff!
It’s good, but lacks a little of that comic book ‘pop’. Because of that it looks flat. Try using a very very light green with opacity on his body- that should push his left arm forward. Use it again on his right (our left) arm and push it a little further back with hue. Should only take a few minutes to do and will add a lot of depth. Second, his head looks a little too big inside his helmet. May want to expand the size of the helmet a bit.
Nice man. The face is the only thing not working for me. It’s popping out more than the helmet and the expression is kind of boring. Other than that it’s a solid piece. Also I don’t know if the original cover was like that, but the crop that cut off right at the crotch and the hand is a little awkward.