Press A + B + Start + Select during game play.

Unlock the Nintendo 64 characters, then check the mini-game screen. More entries should be available. To unlock even more mini-games, win the Junior, Senior, Varsity, and Traveling Leagues in Singles and Doubles.

In order to get the Spin Racket, on the screen that displays the stats of your power, spin, speed, etc., you need to have five more on your spin than your power. When you get the racket, press B to hit a curvy shot.

Complete the game in Singles

Complete the game in Doubles

Defeat the students you face in the Junior, Senior, Varsity, and Traveling Leagues to unlock them at the character selection screen.

Defeat all the Mario characters in exhibition mode, including the Nintendo 64 characters.

Play Donkey Kong's Banana Bunch mini-game and win both levels. When you get to the third level, beat the high score of 60. You can now play on the Jungle Court in linked play and exhibition modes.

Play Baby Mario's Target Shot mini-game and win both levels. When you get to the third level, beat the high score of 60. You can now play on the Tropics Court in linked play and exhibition modes.

Play Luigi's Shooting Star mini-game and win both levels. When you get to the third level, beat the high score of 60. You can now play on the Castle Court in linked play and exhibition modes.

Finish either Mario Challenge (singles is easier if you use the "Drop Shot" trick technique). After that, make sure you have an empty file or one you do not use. You now have the option to pick either Harry or Kate (and make them left or right handed).

After you have completed all of the wall mini-game levels, talk to the girl in front of the door that is preventing you from walking in. She will ask you if you are ready for the master level of practice. Press B and she will ask if want to try for an even easier level of practice. Answer "Yes". Then, walk on any of the level numbers and press A. You will get more experience.

When you are in a singles or doubles match, you can do a Smash Ace when you see a yellow circle. Go on the circle and press B + A.

Get to the Island Open Tournament. Immediately press A + B + Start + Select when the match starts to win that round. Repeat this four times to instantly win the tournament.

Select adventure mode. If the score is 40-0 for your opponents, save and quit. When you restart the game, it will be 0-0 again. The game only counts games and sets.

If you lose a game in RPG mode, pause the game immediately before the score appears. Save the game, quit, then resume the game you were just playing. The game (not match or set) will be reset.