X-Men: The Official Game

Continue on to Act 2 without acquiring three Mutation bars in Act 1 for a certain character. Acquire at least two Mutation bars in Act 2 then go back to an Act 1 level and complete it on a higher difficulty for a 100% level completion. You will be given a Mutation bar, but you will not be allowed to add it because you can only add three bars to each character in Act 1. The game will not let you past this screen or regress any of the bars. You will have to restart the game.

Collect all Sentinal Techs with a character to unlock his or her alternate comic costume.

You can unlock eight danger room missions. You must get all the Sentinel files and Weapon X files with all the 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. Go back on the higher levels to gain the missing mutations, without worrying about racing around trying to find the pieces (especially on timed missions).