Play through the game to unlock the first three Danger Room missions. Six more Danger Room missions are unlocked once you collect all Sentinel files and Weapon X files with every character.
To save time and frustration, run through the level on novice to find all six Tech Pieces, then distribute mutation and save the game. Return to the higher levels to gain the missing mutations, without worrying about racing around trying to find the pieces (especially on timed missions).
In all the missions, except the tutorials, unlock various costumes for Wolverine, Nightcrawler, and Iceman by finding every Sentinel Tech and Weapon X Folders:
COSTUME - HOW TO UNLOCK Iceman's Casual Clothes - Collect all Weapon X Folders as Iceman. Iceman's Comic Clothes - Collect all Sentinel Tech as Iceman. Nightcrawler's Casual Clothes - Collect all Weapon X Folders as Nightcrawler. Nightcrawler's Comic Clothes - Collect all Sentinel Tech as Nightcrawler. Wolverine's Casual Clothes - Collect all Weapon X Folders as Wolverine. Wolverine's Comic Clothes - Collect all Sentinel Tech as Wolverine.
