To unlock this harder bonus level, beat Crack of Doom, get Gandalf, Sam, and either Aragorn, Legolas or Gimli, to level 10. Then, go to the very top of the level select screen (the part with the 5 blue dots past Crack of Doom) and choose the one all the way on the right. Its good to use the codes for Unlimited Health, Perfect Mode, and Unlimited Ammo. It also helps to use Gandalf because he has the shield.