Enter the following codes at the password screen, these codes do not work in Tournament mode. Each letter stands for the first letter of the Turtle's (plus the Shredder 'S')

New outfit for Donatello:
D, S, L, R, D, R, M

New outfit for Leonardo:
L, M, R, M, D, R, D

New outfit for Michelangelo:
M, L, M, R, D, R, M

New outfit for Raphael:
R, M, S, R, M, D, R

Take no damage:
L, S, D, R, R, D, R

Stamina doesn’t 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

Infinite Shuriken:
R, S, R, L, R, S, M

No Shurikens:
R, L, M, R, D, S, L

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

Defense Doubled:
L, D, R, M, R, L, M

Offense Doubled:
S, D, L, S, R, L, L

Super-Tough:
R, D, S, R, M, R, L

Toddling:
S, S, S, M, R, D, D

Abyss, you lose all health for falling:
S, D, S, D, R, L, D

Nightmare, enemy attacks are doubled:
S, L, S, D, R, D, L

Health items are all full pizzas:
M, R, L, M, R, M, R

Playmates added to Bonus Materials:
S, R, M, L, D, D, R