Bonus Nightcrawler Danger Room level:
     Press  Up, Up, Down, Down, Left, Right, Left, Right, Start at the
Cerebro Files menu.

Bonus Iceman Danger Room level:
     Press  Right, Right, Left, Left, Down, Up, Down, Up, Start at the
Cerebro Files menu.

Bonus Wolverine Danger Room level:
     Press  Down,  Down, Up, Up, Right, Left, Right Left, Start at the
Cerebro Files menu.