Ground Control Cheats

At the main menu, press M + S + V. Then, enter one of the following codes at the prompt to activate the corresponding cheat function:
Result
Cheat Code
God mode for all units god
Disable God mode notgod
Unlock all campaign missions in custom game menu gimme maps
Secret sabotage mission unlocked in custom game menu the new generation of rts-games
Flashlight GUI flashlight
Alternate textures from massive with love
Press ~ to display console window console

Repeated click on the fish on the credits screen.

Press the M, S and V keys all at the same time on the main menu to get the cheat box then put in one of the following codes

notgod God mode off
god God mode on
console Makes ~ bring up the console
flashlight Flashlight Mode
gimme maps Go to custom game menu for all campaign missions
the new generation of rts-games Get Secret Sabotage mission in the Custom game menu
from massive with love weird textures

At the main menu press M, S and V keys simultaneously to bring up the code-entering dialog. You may then enter the following codes: console = allows ~ (tilde key) to bring up console:

god = God Mode for all units
notgod = disable God Mode
gimme maps = play all campaign missions in "Custom Game" menu
flashlight = flashlight GUI mode
from massive with love = funny textures
the new generation of rts-games = play secret sabotage mission in "Custom Game" menu