I think this is a great picture! The best part about it is probably how well you get the body proportions down. You seem to show them in the right areas. It just makes more sense from the angle at which the characters are shown. Iron Man probably looks better.
I imagine it would be easier to make more realistic depictions with a robotic like character. At least there was some background. It did look kind of stylistic with how there was this big rectangle of background in the middle. They certainly seem to be in the mood for some action. Marvel is like that.