Mario Power Tennis

Event mode:
Hold Z, then press Start at the title screen.

Ace difficulty:
Win the Planet Cup tournaments in singles or doubles mode.

Star Cup:
Win all three Normal Cup tournaments.

Moonlight Cup:
Win all the Rainbow Cup tournaments.

Bowser court:
Win the Special Cup Fire tournament in singles mode.

Mario Bros. court:
Win the Special Cup Lightning tournament in doubles mode.

Special court options:
Play a special court in the Special Cup to get more options for that venue.

Fly Guy:
Win the Mushroom, Flower, and Star Cup in singles mode.
Rene Campos.

Shy Guy:
Win all three Normal Cup tournaments in singles mode.

Paratroopa:
Win all three Normal Cup tournaments in doubles mode.

Petey Piranha:
Win the Special Cup Fire and Lightning tournaments in doubles mode.

Wriggler:
Win the Special Cup Fire and Lightning tournaments in singles mode.
MAF1222.

Balloon Panic mini-game:
Win the Flower Cup tournaments in singles mode.

Coin Collectors mini-game:
Win the Mushroom Cup tournaments in singles mode.

Mecha Bowser Mayhem mini-game:
Win the Mushroom Cup tournaments in singles mode.

Mecha Bowser Mayhem mini-game: Easy win:
Once you get Petey Piranha it will be easier to win. She is tall enough to hit Bullet Bills when they come out.
WIng722493.

Infinite Balloon Panic Challenge:
Complete Ultra-Hyper Panic.

Infinite Coin Collectors Challenge:
Complete the Gold Rush Challenge.

Infinite Gooper Blooper Volley Challenge:
Complete Master Blooper.

Infinite Terror Tennis Challenge:
Complete Phrantic Phantoms.

Infinite Tic-Tac-Glow Challenge:
Complete the Dazzle Shine Challenge.Star for character:
Win all three Normal Cup tournaments with a character to unlock his or her star version.

Alternate Yoshi's defensive power shot color:
Win the Flower Cup tournaments in doubles mode.

Skip credits:
After you have seen the credits at least once, hold Start + A.
Rene Campos.

Taunts:
Press A or B when your opponent hits the ball.

Random character or court:
To randomize your character or court selection, press X at the character or court selection screen. This will not randomize your character's attributes (Hand or Star) and will not randomize your game mode.

Toad and Toadette appearance:
In the introduction sequence when Wario and Waluigi look at the big scoreboard, you can see Toad and Toadette on the first part to the left on the scoreboard. Note: They are not playable characters.
Marc-André Dion.

Character bloopers:
Play tournament mode and complete the first three championships (Mushroom Cup, Flower Cup, Star Cup) to view the credits, and watch some animated outtakes from the opening FMV sequence. Complete the next three championships you unlock from this (Rainbow Cup, Moonlight Cup, Planet Cup) to view the credits again, but with entirely new outtakes.
Andy L.

Hint: Score easily:
Note: you must be playing a doubles match. Have at least one CPU player on the opposite team. The CPU must be in the position closest to the net. When you are about to return a serve, do a slow shot (B + A) and aim the ball so that it curves far and lands close to the net. The CPU player will either hit the net, or the ball will go far out of bounds depending on the character and difficulty. This usually will work, but the CPU will rarely return it successfully.
Supergolfpencil2.

Use the following trick to get easy wins on the Fire and Thunder cup Gimmick tournaments. Unlock a Star player (for example, Bowser Jr.). Star players are much better. They seem to be better at returning and scoring on the opponent. Win the Fire cup to unlock the Gimmick courts in all exhibition modes. Win the Thunder cup to unlock Wriggler.
Scott Rakestraw.

Hint: Artist on the Court unlockables:
Skye7707.

Bowser and Bower Jr.'s painting: Complete Diddy Kong's painting within time limit.
Diddy Kong's painting: Complete Luigi's painting within time limit.
Luigi Painting: Complete Mario's painting within time limit.
Yoshi's painting: Complete Bowers and Bowser Jr.'s painting within time limit.

Hint: Balloon Panic unlockables:
Skye7707.

Super Panic level: Complete the Panic level.
Ultra-Hyper Panic level: Complete the Super Panic level.

Hint: Chain-Chomp Challenge unlockables:
Skye7707.

Famished Chomp level: Complete Hungry Chomp level with the highest score.
Hungry Chomp level: Complete Perkish Chomp level with the highest score.

Hint: Coin Collectors unlockables:
Skye7707.

Coin Challenge level: Complete the Gold Rush level.
Gold Rush level: Complete the Jackpot level.
Jackpot level: Complete the Fever level.

Hint: Gooper Blooper unlockables:
Skye7707.

Master Blooper: Complete the Rival Blooper level.
Rival Blooper: Complete the Buddy Blooper level.

Hint: Mecha-Bowser Mayhem unlockables:
Skye7707.

Iron Frame level: Complete the Aluminium Frame level.
Titanium Frame level: Complete the Iron Frame level.

Hint: Terror Tennis unlockables:
Skye7707.

Pesky Poltergeists: Score 50 points in the "Goofy Ghosts" level within time limit.
Phrantic Phantoms: Score 150 points in the "Pesky Poltergeists" level within time limit.

Hint: Tic-Tac-Glow unlockables:
Skye7707.

Dazzle Shine level: Score 75 points in the "Sparke Shine" level within time limit.
Sparkle Shine level: Score 50 points in the "Glimmer Shine" level within time limit.
Tic-Tac-Glow Challenge: Score 75 points in the "Dazzle Shine" level within time limit.