Enable the "Mother Mosquito" code. Then, hold L2 and press Up, Right, Left, Down, Square(2), R2(3) at the character selection screen. A shout will confirm correct code entry.
In-game reset
Hold L1 + L2 + R1 + R2 and press Start + Select during game play.
Mother Mosquito
Hold L1 and press Up, Right, Left, Down, Square(2), R1(3) at the character selection screen. A shout will confirm correct code entry.
Special costume
Unlock all alternate costume colors on every level.
Two player mini-game
Hold Start + Select on controller two after turning on the system. Press Square to move forward, X to jump, and Triangle (when the power meter is full) to do a super attack. Alternately, hold L2 and continuously rotate the Right Analog-stick clockwise at the title screen.
Unlock Cycle Minigame
At the title screen, press and hold L2, and then rotate the right analog stick 30 times. If done correctly, you'll hear a chime and automatically go to the cycle minigame.
Year 2
Fill each of the sixteen Ex Tanks to unlock Year 2.