Super Smash Bros. Brawl/The Great Maze

Go through any doors in no particular order, defeat who's inside. (To know if there's a battle, there will be black mist coming out of the door.) Just make sure you're prepared for lots and lots of battles. You can replenish lives and damage by going to a save room, some rooms also contain teleports to warp to other save points. Once you go through everyone and every door, go to the very center and enter the Boss battle!