Wow! This is really good.
You have some problems with proportions (Captain America's head looks much bigger tan Leon's) and anatomy (Lion's left leg shouldn't be ale to be that way without the hip rising a little and turning towards the camera), but overall it is very well done.
The thing that bugs me the most is the background. Doesn't make too much sense to me. Also, the lighting on the background (From the bottom) is completely different form the character's (from the top)
Keep up the good work!