First to make codes work, set Cheats to "On" in the Skirmish/Multiplayer setup screen. Then hit these key combinations to activate.

Code - Effect

CTRL + ALT + B Bling Bling - Max out your resources, increase Mass/Energy capcity by 10,000.
CTRL + DELETE Delete units - Target a unit then delete it.
ALT + F2 Spawn Menu - Aim where you want to spawn a unit, then hit this and you can spawn any unit under anyone's control.
ALT + N Toggle Damage - Makes all units in the game invulnerable, including your enemy's.
ALT + A Toggle Opponent AI - Units will follow orders given before command is used, but commander will not issue anymore.