Pause the game during any mini-game and press A, B, X, R, Y. You will be able to make any changes to mini-games. For example, on the 1 vs. 3 game Flatiater, you can change your ball into squares and triangles; allow the runner to jump or drive cars; or make the field bigger, be in space, etc.
Successfully complete the game on the normal difficulty setting in Battle, Flag, or Robo Rabbit Hunt to unlock the hard difficulty setting in that category.
Successfully complete story mode on the hard difficulty setting to unlock the intense difficulty setting.
Successfully complete story mode to unlock Bowser's Nightmare.
Successfully complete Bowser's Nightmare in story mode to unlock Frightmare.
Win Battle, Flag, and Robo Rabbit Hunt on all difficulty settings to unlock Skoler and his parts at the shop in super duel mode.
Defeat DK in battle mode on the hard difficulty setting in super duel mode to unlock DK and his parts at the shop in super duel mode.
While playing the game, press L when it is not your turn to taunt.
At the choose your mode screen, go to Malmar the star with the bow on her head then select what you want to play. Note: In Beach Volleyball, you can choose your ball and how many pints you need to win.
When Shy Guy holds up a sign, quickly pause the game to see what he is holding up. When this is done correctly, you will win.
You will get a point for each mini-game you play in super duel mode. Play in party mode and have a game for 50 turns. Make all characters CPU controlled and leave. Let the CPU play and they will get points without you doing anything. You will get 50 points to spend in super duel mode.
The more mini games you play in any kind of mode besides free play, the more points you will get towards the type of any games you win. Note: Battle points are the hardest to get.
Use the following trick to defeat Bowser at end of story mode. Bowser starts by sending lots of fire-breathing Koopas after you. To defeat them, jump on their heads. However, make sure that they are not about to breathe fire or you will lose a heart point. This is followed by three fire rings that can expand, contract, or spin in any variety, and you must jump over them. After that, Bowser breaks out of the screen and begins to attack you by jumping on you, running into you, or breathing a lot of fire. You can avoid all those attacks by running around him in circles, but do not get too close or his spikes will hurt you. Notice the blocks that he jumps on will start to break; after he jumps on the same one three times, he falls through. Finally, he drinks a potion to make him huge. The red fireballs he throws out of his right paw can be picked up once they cool off. However, if you wait to pick them up after he starts to shoot fire, they will be reactivated and you can pick them up and throw them at him by pressing B button, by jumping and throwing on the little circle in front of the ledge near his nose. Do this five times, and you will succeed.