Gold Saved Game:
Highlight a file at the saved game selection screen. Keep the file highlighted during the duration of the code. Hold Nunchuk C and press 1 three times, then release the button. Hold Z and press 1 four times then release the button. Hold C + Z and press 1 five times. All four gems should appear to confirm correct code entry. Select that saved game file and enter the sport selection screen and everything will be gold.
Unlock Hard Mode:
Complete all cups on normal.
Unlock Sports Mix mode:
Complete tournaments in every sport and defeat Behemoth.
Unlock Golden Sport Sets:
Complete Tournament mode under the Normal and Hard difficulty for a sport set to unlock the Golden version of that sport set.
Unlock Behemoth character:
Complete the tournaments in every sport to face Behemoth from Final Fantasy.
Unlock Black Mage character:
Complete Star Road, located on the Star Cup map twice in tournament mode. Complete Star Road 3 times to unlock him for the other 3 sports.
Unlock Cactuar character:
Play 60 games or defeat him on a hidden path in tournament mode.
Unlock Moogle character:
Clear the Mushroom Cup Slime - Play 28 games or defeat him on a hidden path in tournament mode.
Unlock Ninja character:
Complete Star Road, located on the Star Cup map once in tournament mode.
Unlock Slime character:
Win 28 games
Unlock Rosalina character:
Win all mini-games in Basketball, Volleyball, Hockey, and Dodgeball (in order).
Unlock White Mage character:
Complete Star Road, located on the Star Cup map twice in tournament mode.
Unlock Bowser's Castle stage:
Defeat Bowser in the Star Cup.
Unlock Daisy Garden stage:
Complete the Flower Cup. This stage is not compatible with Volleyball.
Unlock Ghost Ship stage:
Play 40 matches.
Unlock Koopa Beach stage:
Complete a match that is played on Koopa Beach in Tournament Mode.
Unlock Peach's Castle stage:
Complete the Mushroom Cup.
Unlock Starship stage:
Complete the Star Cup.
Unlock Waluigi Pinball stage:
Play 35 matches. This stage is not compatible with Basketball.
Unlock Wario Factory stage:
Complete a match that is played on Wario Factory in Tournament Mode.