Switch boomerangs:
Throw boomerangs and switch turtles while they are in-flight. The new turtle will catch the boomerangs and place them in his inventory.

Duplicate pizza:
Enter a sewer, take a pizza, then exit. Return to the same sewer to find the same pizza again.

Eliminate Roller Car:
Press Select to exit the Turtle Wagon on level 3, after a Roller Car appears. The other car that was approaching you will disappear. Note: You must be close to the other car.

Cheat mode:
Press Up(2), Down(2), Left, Right, Left, Right, A, B, Start at the title screen.

Level select:
Press Down(5), Right(7), B, A, Start at the title screen.

Go into the water:
Get close to the water, then press Start, Right(5), Down(5), Up(2), Down(2), Select, Start.