Various cheats
     At  the  main menu select "New Game" and enter the following (all
directions on d-pad while holding L, R, and Z).

Left, Up, Down, A, Right, B, Start
A text box will open where you inter the cheat you want:

Cheat code:        Effect:
WHERESMAX          All models and medals
WEWILLWIN          All levels unlocked
MISSMACROSS        All paint schemes
MIRIYA             Missiles and Gunpod power faster
SPACEFOLD          Gunpod powers up faster
MARSBASE           Missiles regenerate faster
BACKSTABBER        Enemies are destroyed after one hit from Gunpod
SNIPER             One shot kills in sniper mode
SUPERMECH          Invincibility
CLEAR              Turn off cheats
MULTIMAYHEM        All multi-player levels unlocked
FLIPSIDE           Upside down mode