I also love the colors and the textures--the flower at the top of the skull is my favorite. It's great that you can figure out how to do something as awesome as this with just your imagination and the internet. I look forward to seeing more of your projects!
First project? You have way more patience than I do, because this is a huuuggee project! I love the expression that each superhero has, but the Hulk is my favorite. I can't wait to see what your second project is.