Beautiful piece. I love the perspective and the way it focuses around Stan Lee; but the composition doesn't give the impression that the other characters are "pressed" and crowded around him. And having both Gwen and Mary Jane there is... nice, very, very, very nice, a lovely tribute. My compliments!
This looks really beautiful overall, and I like a lot of the details and the coloring is gorgeous, but why does Sue have such a wedgie and like no stomach? And what's up with her right leg? Her right butt-cheek shouldn't be visible if we can see that much of her right thigh. She could be turned more towards Stan to better explain why so much of her thigh is visible.