Pause the game and press R1(2), L1, R1, L1(2), R1, L1, R1(2), L1, R1, L1(2), R1, L1 to unlock the "Cheats" selection at the options menu. The cheat options include "Toggle Unit Spying", "Cheat Win", "Gimme $10000", "Show LZs", "Player Invulnerable", "Enable All Levels", and "Clear Fog Of War".