Casey Jones...
	Evil Turtlebot...
	Holiday Outfits...
	Hun...
	Oroku Saki...
	Passwords...
	Shredder...
	Splinter...
	Unleash the Secret of Gembu...
	Unlock Challenge Mode...
	Unlock Characters For Vs. Mode...
	Unlock Levels for Story Mode S...
	Yoshi Hamato...

Successfully complete level 1 as Raphael to unlock Casey Jones in versus mode. He does not have any Dojo missions in his story and does not get nearly as many intermission sequences as the turtles, but he is much stronger. Also, you cannot have another player play as your "assist" character when you are Casey Jones. He is the best all-around single player character, as he takes out most enemies with a single hit.

Successfully complete level 3 as Raphael, Donatello, Michaelangelo, or Leonardo to unlock the Evil Turtlebot in versus mode.

Change your system's date to either December 24th or 25th to see the turtles in Santa garb. Change it to October 31st to wear a pumpkin on your head.

Successfully complete level 6 as Michaelangelo to unlock Hun in versus mode.

Defeat Saki as Raphael, Donatello, Michaelangelo, or Leonardo to unlock Oroku Saki in versus mode.

Use the following key when entering the passwords.

L: Leonardo
M: Michaelangelo
D: Donatello
R: Raphael
S: Splinter

Alternate Donatello costume:
Enter SRSMM as a password. Hold L or R when selecting Donatello at the character
selection screen.

Alternate Leonardo costume:
Enter RMMLL as a password. Hold L or R when selecting Leonardo at the character
selection screen.

Alternate Michaelangelo costume:
Enter DLDSM as a password. Hold L or R when selecting Michaelangelo at the
character selection screen.

Alternate Raphael costume:
Enter LMSDD as a password. Hold L or R when selecting Raphael at the character
selection screen.

Donatello has larger bandanna and double attack power:
Enter SMLLR as a password.

Leonardo has larger bandanna and double attack power:
Enter SLDDS as a password.

Michaelangelo has larger bandanna and double attack power:
Enter SMRDL as a password.

Raphael has larger bandanna and double attack power:
Enter SRRLR as a password.

Donatello has smaller bandanna and double defense power:
Enter LLSMR as a password.

Leonardo has smaller bandanna and double defense power:
Enter MLLSR as a password.

Michaelangelo has smaller bandanna and double defense power:
Enter MRLLD as a password.

Raphael has smaller bandanna and double defense power:
Enter LSMDR as a password.

Donatello flashes red and has attack power-up:
Enter DRLDS as a password.

Leonardo flashes red and has attack power-up:
Enter LMLSD as a password.

Michaelangelo flashes red and has attack power-up:
Enter MSRMM as a password.

Raphael flashes red and has attack power-up:
Enter RDSRL as a password.

Leonardo has unlimited normal shuriken:
Enter MSSRD as a password.

Michaelangelo has unlimited exploding shuriken:
Enter MRRSL as a password.

Master Spinter:
Enter LLMSR as a password to unlock Master Splinter in story mode.

Playmates toy database:
Enter LSDRM as a password.

Alternate hit sound effects:
Enter LSLSS as a password.

Defeat Shredder as Raphael, Donatello, Michaelangelo, or Leonardo to unlock Shredder in versus mode.

Successfully complete Dojo level 3 as Leonardo to unlock Splinter in versus mode.

Beat the third Dojo Stage with all four turtles to learn the Secret of Gembu maneuever. Use the move to damage everyone on the screen. You'll have three opportunities per level to use it.

To unlock Challenge Mode, defeat Story Mode with all four turtles.

Fulfill the following criteria to unlock the corresponding characters for Vs. Mode:
Casey Jones: Beat Stage 1 with Raphael
Evil Turtlebot: Beat Stage 3 with any turtle
Hun: Beat Stage 6 with Michaelangelo
Splinter: Beat Dojo Stage 3 with Leonardo
Shredder: Beat Shredder with any turtle
Oroku Saki: Beat Saki with any turtle
Yoshi Hamato: Beat Challenge Mode with any turtle

Complete a level to unlock it in Stage Select.

Successfully complete Challenge Mode as Raphael, Donatello, Michaelangelo, or Leonardo to unlock Yoshi Hamato in versus mode.