Here are some cheats and tips for the game Teenage Mutant Ninja Turtles 3: The Manhattan Project.
Cheat mode:
Press Up(2), Down(2), Left, Right,
Left, Right, A, B, Start at
the title screen before the demonstration starts. Note: For two
player mode press Up(2), Down(2), Left, Right,
Left, Right, A, B, Select,
Start. Level select, extra lives, and sound test options
will now be available.
Auto turtle selection:
Press Down(5) at the character selection screen, or
Down(10) at the same screen for two player mode. After
a turtle is defeated, the next turtle will automatically be selected
randomly. Alternately, rapidly tap Left, Right
repeatedly at the character selection screen.