The thing about the Fantastic 4 slot is the innovative free spin feature. When you get 3 or more planet symbols in your view (remembering Cryptologic's Silver Surfer game) you get 12 free spins (no re-trigger). During free spin, the center reel has a stacking symbol, and when one of the magic 4 stacking symbols landed, you will get 4 additional spins with special features.

The extra special features are different: Mr. Fantastic adds an ever-increasing wildness to each reel, Invisible Woman adds an additional multiple to each win, and The Thing adds a sticky wild (but only 3 rotations). The Human Torch converts all characters into all the characters that roll into the human torch and make the first reel wild.