Find a doorway that has a pizza slice or full pizza right at the beginning. Enter, grab the pizza, and exit. If you go back in the pizza will regenerate. Use this to restore power to all your turtles.
Giant Mouser boss glitch
The Giant Mouser at the end of level 4 can be beaten even more easily than normal with this trick. Just stand under him and wait for his mouth to open. When his mouth opens to reveal the "weak spot", pause the game. Unpause the game, and the Mouser's mouth will be closed again, but his weak spot will be slightly visible from behind his mouth. You can now hit it to cause damage while his mouth is closed! Repeat this every time he opens his mouth for an easy victory.
Remove Crushers in Level 3
Go to the third level and hop in the Party Wagon. Whenever you see a pesky Crusher drive around, press SELECT. You will exit the car, and the Crusher should vanish from the screen.
Share Boomerangs
When you get the boomerangs, throw up to 3 of them in the air, then switch turtles, and have the new turtle catch them. The new turtle will be able to use those boomerangs without having picked up a boomerang icon.
Easy way to restore power...