Been playing Marvel Ultimate Alliance 2 a lot and its going to be a long game to platinum. So far I've put about 50 hours in and I'm not even halfway through some of the challenges. The 276 fusions for every possible character combination and collecting 200 team boosts will take the longest. Have a couple more chapters left on Super Heroic difficulty and then I'll unlock Legendary. I believe it will take at least 100 hours to do everything.