[Epixha]

The opacity looks messed up at almost every part. High contrast, low brightness, dark curves and deep exposure, white elements, they never work together. Some elements like the smoke above Iron Man's arm (not the one on the arm) could be used at a better place, because it looks extra there. You should also increase the opacity of Iron Man and remove the shadows around it's extremes. It also looks like you erased some parts of Iron Man, to blend with the background, which didn't quite work as well. Almost all the elements used have low opacity, especially if you look at the right shoulder, you will not be able to understand what's there, it looks messy. A better background could be used, perhaps. Masks are poorly used.
However, I like the lighting, that should be the best part of this. Especially the one on the eye.