First press the ~ (Tilde) key (just like in Quake 1 & 2, Unreal, Half-life, etc.). Then enter the code:

/wuss = All weapons
/save # = saves game to specified slot #
/load # = loads game from specified slot #
/superfuzz = God mode
/wallflower = No target
/health 999 = 999 Health
/nocollision = No clip mode
/spawn cookies = creates cookies
/spawn heligun = spawn the gun from the helicopter

Likewise for the heligun (bind to different key).

/spawn coin = Gives a coin
/spawn magnum = Gives the Magnum
/spawn health = Gives a healthpack
/spawn rockets = Gives Rockets
/spawn shotgun = Gives the Shotgun
/spawn cookies = Gives a pack of cookies
/spawn heligun = Gives the big gun from the chopper
/spawn lensflare = Makes a light-effect
/spawn sniperrifle = Gives the Sniperrifle
/spawn assaultrifle = Gives the Assaultrifle
/spawn rocketlauncher = Gives the Rocketlauncher
/spawn reactiveshields = Gives the ReactiveShield


Here are all the items that you can get via "/spawn ":

Code = ??
Dollar = coin
Decoder = ??
KeyRing = small key
Envelope = ??
BlueCard = blue Identcard
Chemsuit = protection suit
Evidence = papers with evidence
MoneyBag = bag from bank robbery
Silencer = silencer for standard gun
ChainGun = chaingun (the one you get with the 5=key)
IdentCard = ??
GreenCard = green
U4 sample = sample from chemplant
OrangeCard = orange
YellowCard = yellow
PulsePart2 = second
PulsePart1 = first part of Pulse Cannon
PulsePart3 = third (as soon as all three parts are picked up, the weapon is ready)
Blueprints = blueprints from constructionsite