In this mode, you pick your character and must defeat every character in the
game with one life and only three chances to recover damage. Sound hard Well,
it is.

Here's how it works: After every battle, you'll get dropped off at the Rest
Station. Here you'll see a billboard of who you'll face in the next battle, as
well as three 0% Heart Containers. While most HCs only replenish 100% damage,
these guys will reset your damage to 0%. The catch, of course, is that you only
get three throughout the whole challenge (5 in co-op mode). Step into the light
in the middle of the room to move on to the next battle.

The order in which you face your opponents is decided based on the order of
release of each universe in Smash Bros. (Japan-wise). This is the order:

Battle 1: Mr. Game & Watch
Battle 2: Mario, Luigi, Peach, Bowser
Battle 3: DK, Diddy
Battle 4: Ice Climbers
Battle 5: R.O.B.
Battle 6: Link, Toon Link, Zelda/Sheik, Ganondorf
Battle 7: Samus/ZSS
Battle 8: Pit
Battle 9: Snake
Battle 10: Ness, Lucas
Battle 11: Marth, Ike
Battle 12: Yoshi
Battle 13: C. Falcon
Battle 14: Sonic
Battle 15: Kirby, Meta Knight, Dedede
Battle 16: Fox, Falco, Wolf
Battle 17: Wario
Battle 18: Pikachu, Jigglypuff, Pokemon Trainer, Lucario
Battle 19: Olimar (2 in co-op)

Note that you can face either Zelda or Sheik, but not both. Same with Samus and
ZSS. But you must face all three of PT's Pokemon.

Although the battles are predetermined, the stages (a random stage from the
universe that's not a Past Stage) and the order of characters (you only ever
fight two people at a time) are not.