The cheats of the base version also work in the addon.

Press [Enter] during game play in single player mode. Then you might type in:

fortknox                Additional $1,000
keyholemaster           Full map
yeepeekaye              Launch a super weapon (nuclear bomb) at the pointer
ineedalltechnos         Unlimited money and entire tech tree unlocked
motherrussia            Spawn Russian T-80 tank
coolihaveanewcar        Spawn CIA Armored SUV
swatatyourorders        Spawn S.W.A.T. member
greenjelly              Spawn British cop
blackhawdown            Spawn SA12 Anti-Aircraft Missile Launcher
duckhunt                Spawn Duck
ymca                    Spawn U.S. police officer
bringoutthedead         Spawn British Ambulance
coolimthepresident      Spawn a US president
bigbrother              Unlock camera mode