Teenage Mutant Ninja Turtles 2: Battle Nexus cheats and cheat codes for Gamecube

Cheats:
Enter the following keys at the password screen
R: Raphael
S: Shredder
L: Leonardo
M: Michaelangelo
D: Donatello

Effect - Password
Abyss - S D S D R L D
Challenge Endurance - No more stamina restore - M R M D R M D
Health - D S R D M R M
Fatal Blow - L R S R D R D
Unlimited Shuriken - R S R L R S M
Lose Shuriken - R L M R D S L
Mighty Turtle - L S D R R D R
New skin for Donatello - D S L R D R M
New skin for Leonardo - L M R M D R D
New skin for Michelangelo - M L M R D R M
New skin for Raphael - R M S R M D R
Nightmare - S L S D R D L
Pizza Paradise - M R L M R M R
Playmates in Bonus Materials - S R M L D D R
Poison - D R S L L S R
Self Recovery - D R M S R L R
Squeaking - M L D S R D M
Double Defense - L D R M R L M
Double Offense - S D L S R L L
Super-Tough - R D S R M R L
Toddling - S S S M R D D

Unlock Casey Jones as playable character:
Beat the Open Brawl Tournament 

Unlock Karai as playable character:
Beat the Foot Fight in Tournament Mode.

Unlock Slashuur as playable character:
Beat the Battle Nexus Tournament in Tournament Mode.

Unlock Splinter as playable character:
Win the game once

Character's Feet Pass Through Wall:
Whenever you do a wall-jump, look very carefully to see that your character's 
toes (or sometimes even their feet) are passing through the wall.

Teenage Mutant Ninja Turtles arcade game:
Find the Teenage Mutant Ninja Turtles arcade game during Mission 9-1 
and use it to play the classic arcade game.