Iceman Danger Room missions
At the Cerebro Files menu, press Right(2), Left(2), Down, Up, Down, Up, Start to unlock the bonus Iceman Danger Room missions.
Nightcrawler Danger Room missions
At the Cerebro Files menu, press Up(2), Down(2), Left, Right, Left, Right, Start to unlock the bonus Nightcrawler Danger Room missions.
Wolverine Danger Room missions
At the Cerebro Files menu, press Down(2), Up(2), Right, Left, Right, Left, Start to unlock the bonus Wolverine Danger Room missions.
Danger Room missions
Successfully complete an Act with a character to unlock one of their Danger Room mission. Successfully complete all three Acts with a character to unlock all three of their bonus Danger Room missions.
Bonus costumes
Collect all Weapon X files with a character to unlock their street costume. Collect all Sentinal Techs with a character to unlock their comic costume.