Complete all sixteen practice rounds. The background color will turn red to confirm correct code entry. Enter the options screen and select the "Floor" option to choose a new floor pattern and background color.
Enable the "Alternate floors" code. Complete all modes except practice and multiplayer and achieve an "OK" rating. The background color will turn green to confirm correct code entry. Select any game mode other than practice mode. Select the man that represents the pieces to change him into a duck. Begin game play with triangle, rectangular, and square-shaped pieces.
Hold C-Up or C-Down at the main menu to raise or lower a whirlpool of water. Keep holding either button and press the Analog-stick to move the whirlpool across the water.
Thanks to Revolution reader Klobbob22!