Invincibility Headgear
If you purposely lose a total of 100 matches in single player mode, you unlock special headgear that can be equipped to make you invincible. To equip the headgear, select "Career" from the main menu, "Options" and "Gift." Check the box in the bottom left corner of the headgear.
Health Between Rounds
Press the "-" button on the Wii Remote in between rounds. You will hear a chime sound. At the start of the next round you will have recovered more health than you normally would have between rounds. This can only be done once per match.
Health After Knockdown
Any time an opponent is knocked down, alternate tapping the "1" and "2" buttons on the Wii Remote or shake the Wii Remote and Nunchuck in a drumming motion. This will give your fighter extra health.
Prevent a T.K.O.
At the moment you get knocked down for the third time in a round, alternate tapping the "1" and "2" buttons on the Wii Remote or shake the controllers in a drumming motion. If you do this at the right time, and the match is fairly close, you will remain standing and regain half of your health. This can only be done once per match.
Last Stand Mode
Win the minor, major and world circuits to unlock the "title defense" mode. Defeat Mr. Sandman in this mode to unlock last stand mode. In this mode you will face a series random opponents with a health bar that never regenerates.
Unlock Donkey Kong
As you defeat opponents in last stand mode, you eventually have to go up against the gorilla Donkey Kong. Afterwards, he also becomes a fighter in the exhibition mode. He can be selected from the opponent selections screen.