Note: These cheats require that you complete the game before they are functional.

Activate cheats:
During the mission/level, the [esc] key to pause the game. Press and hold the following three keys:
left [ctrl]
left [shift]
left [alt]

Enter the following numbers on the keypad, if it works, you'll hear a clang of metal.

Perfect mode:
5, 9, 6, 4

Always devastating:
6, 8, 6, 9

All upgrades:
8, 9, 6, 7

Unlimited missiles:
7, 7, 9, 5

God mode:
7, 5, 7, 8

Target mode:
9, 5, 8, 7

Unlock four-hit combo for Aragon:
Pause the game and press 8, 7, 6, 9