Holy crap, that's amazing. All the shading looks really good too. Did you use a reference picture? I would want to imitate this drawing but it's such a complex piece Im don't think I could pull it off.
i LOVE that we still have artists that don't use the movie designs of these characters...I love the exaggerated ears on Wolverine...ooh, and i just noticed you didn't make it all one large flap...i like how you have that curve in the mask...umm, i have NO real way to describe it other than hand signals...which you can't see...god, i'm rambling...i need my cereal...well...awesome pic