Various cheats

L = Leonardo
M = Michaelangelo
D = Donatello
R = Raphael
S = Shredder

Full Health:
Enter DSRDMRM as a password.

Self Recovery (Regain health slowly):
Enter DRMSRLR as a password.

Mighty Turtle (Invincibility):
Enter LSDRRDR as a password.

Squeaking (Alternate hit sounds):
Enter MLDSRDM as a password.

Pizza Paradise (All items turn into pizzas):
Enter MRLMRMR as a password.

Toddling (Alternate walk sounds):
Enter SSSMRDD as a password.

Super-Tough (Enemies have double defense):
Enter RDSRMRL as a password.

Nightmare (Enemies have double attack):
Enter SLSDRDL as a password.

Fatal Blow (Enemies have one hit kills):
Enter LRSRDRD as a password.

Abyss (Lose all health when falling):
Enter SDSDRLD as a password.

Poison (Lose health slowly):
Enter DRSLLSR as a password.

Super Offense Power (Double attack):
Enter SDLSRLL as a password.

Super Defense Power (Double defense):
Enter LDRMRLM as a password.

Challenge Mode Endurance(No stamina restore):
Enter MRMDRMD as a password.

Infinite Shuriken:
Enter RSRLRSM as a password.

No Shuriken:
Enter RLMRDSL as a password.

New Nexus outfit (Donatello):
Enter DSLRDRM as a password.

New Nexus outfit (Leonardo):
Enter LMRMDRD as a password.

New Nexus outfit (Michelangelo):
Enter MLMRDRM as a password.

New Nexus outfit (Raphael):
Enter RMSRMDR as a password.