It's one thing to have 100+ characters, but it's another entirely to make them all play differently. That's apparently the case in Lego Marvel Super Heroes--TT wants to capture what makes the characters different, and to let you truly feel as though each of the unlockable characters is unique.
The first level's Hulk and Iron Man had totally different styles. Hulk is a "big fig," meaning he's a good double the size of other Lego pieces, and he can pick up large objects, throw them, and, of course, smash. He can also turn back into Bruce Banner (in an adorable animation), who can do things that Hulk can't, like build and use computers. Iron Man, on the other hand, plays like you'd expect him to, flying around and firing missiles from the sky. When Spider-Man was unlocked he came with his own suite of skills, allowing him to activate his Spider Sense, climb objects, and zip around with his webs.