I finished the Mount, Morlock Tunnel Raid, and Juggernaut vs. Muir Island missions.

The Morlock Tunnel Raid was annoying. At the end, you have to fight Marrow and four physical resistant cronies. You have to kill the five of them not once, but FOUR TIMES, and that's if you're lucky. After you knock them all down, one of four revivers appears, and you have to beat the shit out of them before they vanish again, which means it will come back and revive the party again when you knock them all down. I think I had to kill them five times. Because of the physical resistant cronies, my original team of Wolverine, Cyclops, Gambit, and Colossus wasn't working (I mostly played as Cyclops during this, since the computer's too stupid to use his eye beam to wipe out the cronies in two hits). I switched out Gambit and Colossus for Storm (who I hadn't used since the Alaska mission in the beginning) and Nightcrawler. Worked wonders.

The Juggernaut one was another Button Mash fest, but this time there was a comic book and Danger Room disc to pick up.

Colossus is confusing in this game. One minute he's holding up a nuclear reactor, the next minute you have to upgrade his Might status before he can lift a large box. He also said something about preferring his "flesh and blood" form. Could've fooled me, because any time you find him in the mansion he's metal. I'm not sure if it was just a programming thing, because Iceman hangs around the mansion in his flesh form.