At the title screen, press Up(2), Down(2), Left, Right, Left, Right, B, A. If you entered the code correctly, the word ''Yeah'' will appear. Movement sounds in story mode will now be different.
Alternate Donatello costumeEnter Splinter, Raphael, Splinter, Michaelangelo, Michaelangelo as a password. Hold L or R when selecting Donatello at the character selection screen.
Donatello has larger bandanna and double attack powerEnter Donatello, Raphael, Leonardo, Donatello, Splinter as a password.
Donatello has smaller bandanna and double defense powerEnter Splinter, Splinter, Splinter, Michaelangelo, Raphael as a password.
Donatello flashes red and has attack power-upEnter Donatello, Michaelangelo, Donatello, Raphael, Splinter as a password.
Alternate Leonardo costumeEnter Raphael, Michaelangelo, Michaelangelo, Leonardo, Leonardo as a password. Hold L or R when selecting Leonardo at the character selection screen.
Leonardo has larger bandanna and double attack powerEnter Leonardo, Michaelangelo, Leonardo, Splinter, Donatello as a password.
Leonardo has smaller bandanna and double defense powerEnter Michaelangelo, Raphael, Leonardo, Leonardo, Michaelangelo as a password.
Leonardo flashes red and has attack power-upEnter Leonardo, Splinter, Leonardo, Splinter, Raphael as a password.
Leonardo has infinite normal shurikensEnter Splinter, Michaelangelo, Raphael, Donatello, Michaelangelo as a password.
Alternate Michaelangelo costumeEnter Raphael, Raphael, Leonardo, Michaelangelo, Donatello as a password. Hold L or R when selecting Michaelangelo at the character selection screen.
Michaelangelo has larger bandanna and double attack powerEnter Splinter, Michaelangelo, Raphael, Donatello, Leonardo as a password.
Michaelangelo has smaller bandanna and double defense powerEnter Michaelangelo, Raphael, Raphael, Michaelangelo, Leonardo as a password.
Michaelangelo flashes red and has attack power-upEnter Michaelangelo, Michaelangelo, Splinter, Leonardo, Raphael as a password.
Michaelangelo has infinite fire shurikens and pizza always appearsEnter Donatello, Raphael, Donatello, Splinter, Splinter as a password.
Michelangelo has improved weaponEnter Michaelangelo, Splinter, Raphael, Michaelangelo, Michaelangelo as a password.
Alternate Raphael costumeEnter Leonardo, Michaelangelo, Splinter, Donatello, Donatello as a password. Hold L or R when selecting Raphael at the character selection screen.
Raphael has larger bandanna and double attack powerEnter Raphael, Donatello, Splinter, Raphael, Leonardo as a password.
Raphael has smaller bandanna and double defense powerEnter Leonardo, Raphael, Michaelangelo, Donatello, Splinter as a password.
Enter Splinter, Leonardo, Donatello, Splinter, Michaelangelo or Michaelangelo, Splinter, Leonardo, Leonardo, Raphael as a password.
Play as Master SplinterEnter Michaelangelo, Splinter, Raphael, Leonardo, Splinter or Splinter, Leonardo, Donatello, Splinter, Michaelangelo as a password to unlock Master Splinter in story mode. Note: You must first complete story mode game as all four turtles.
Alternate hit sound effectsEnter Splinter, Michaelangelo, Michaelangelo, Raphael, Splinter as a password.
Playmates toy databaseEnter Leonardo, Splinter, Donatello, Raphael, Michaelangelo as a password.
Challenge modeSuccessfully complete story mode with Raphael, Donatello, Michaelangelo, and Leonardo to unlock challenge mode.
Play as Casey JonesSuccessfully complete level 1 with Raphael to unlock Casey Jones in versus mode.
Play as Evil TurtlebotSuccessfully complete level 3 with Raphael, Donatello, Michaelangelo, or Leonardo to unlock the Evil Turtlebot in versus mode.
Play as HunSuccessfully complete level 6 with Michaelangelo to unlock Hun in versus mode.
Play as Oroku SakiDefeat Saki with Raphael, Donatello, Michaelangelo, or Leonardo to unlock Oroku Saki in versus mode.
Play as ShredderDefeat Shredder with Raphael, Donatello, Michaelangelo, or Leonardo to unlock Shredder in versus mode.
Play as SplinterSuccessfully complete Dojo level 3 with Leonardo to unlock Splinter in versus mode.
Play as Yoshi HamatoSuccessfully complete challenge mode with Raphael, Donatello, Michaelangelo, or Leonardo to unlock Yoshi Hamato in versus mode.
Alternate costumesSet the GameCube system date to December 25 to see the turtles with a Christmas theme. Set the GameCube system date to October 31 to see the turtles with a Halloween theme.
Secret of GembuSuccessfully complete the third Dojo Stage with all four turtles to learn the Secret of Gembu move. Use it to damage everyone on the screen. Note: This can only be done three times per level.
Wrong voiceWhen you select Michaelangelo and pick up a recovery item such as pizza, etc., he will have Leonardo's voice instead of his original one.
