Full energy:
Pause game play and press Up(2), Down(2), Left, Right, Left, Right, B, A, Start. Note: This may only be enabled once per game.

Practice bonus games:
Press A + B + Select at the configuration screen. Select the question mark that appears on the screen with the five regular stages.

Invisible turtle:
Turn on the Game Boy, then hold Select + A + B. Continue to hold those buttons and press Start until the level selection screen appears. Choose level 2, then release all buttons when game play begins. Get to the point where your character only has one unit of energy remaining and go to the bonus stage on the left side of the fourth smasher. Press A + B + Select + Start while flashing to reset the game. Continue to hold A + B + Select, choose a level, and select Leonardo as a character. Continue to hold A + B + Select + Right until game play starts.

Hint: Bonus areas:
Perform the following tasks to reach extra areas in the game.

Level 1
Destroy the second oil barrel and walk into the remains.

Level 1-2
Locate and walk under the first ledge as far as possible.

Level 2
Locate the large pipes that move vertically. Jump on top of the second pipe that is moving vertically. Jump to the left when the pipe reaches its highest point.

Hint: Hidden mini-game:
On level 1-4, jump into the first spot of water and walk as far right as possible. This will take you to a mini-game to regain your energy.