This edits a critical game file. Carry on at your own risk.

Locate the config.cfg file in the COD2 directory - a focused file search will find it easily. Open it using Notepad and locate the "seta mis_01" string. Set the value of that string and all other "seta_mis_" lines following it to 10 or higher to unlock those stages on Veteran difficulty. It would appear like:

////////////////////////////////////
seta mis_01 "13"
seta mis_02 "13"
seta mis_03 "13"
seta mis_04 "13"
seta mis_05 "13"
seta mis_06 "13"
seta mis_07 "13"
seta mis_08 "13"
seta mis_09 "13"
seta mis_10 "13"
/////////////////////////////////////

In the game's options menu, enable the console. While playing, drop the dev-console via the tilde key and input developer 1 to enable code recognition. The following codes may be entered for effects. These codes are only valid for version 1.0 of COD2 and may be altered or removed from later versions. (Unverified)

god ... Player invulnerability on/off
give all ... Player accrues all weapons
give ammo ... Player accrues all current weapon ammo
ufo ... Player may swim/fly through game world
noclip ... Player may clip through environment
notarget ... Player is invisible to enemy entities
moscow ... Start on the map Red Army Training
demolition ... Start on the map Demolition
decoytrenches ... Start on the map The Diversionary Raid
decoytown ... Start on the map Holding The Line
elalamein ... Start on the map El Alamein
eldaba ... Start on the map The End Of The Beginning
tankhunt ... Start on the map Repairing The Wire
trainyard ... Start on the map Railroad Station No. 1
downtown_assault ... Start on the map Downtown Assault
cityhall ... Start on the map Stalingrad City Hall
downtown_sniper ... Start on the map Comrade Sniper
libya ... Start on the map Crusader Charge
88ridge ... Start on the map 88 Ridge
toujane_ride ... Start on the map Armoured Car Escape
toujane ... Start on the map Retaking Toujane
matmata ... Start on the map Assault On Matmata
duhoc_assault ... Start on the map The Battle Of Pointe Du Hoc
duhoc_defend ... Start on the map Defending The Pointe
silotown ... Start on the map The Silo
beltot ... Start on the map Prisoners Of War
crossroads ... Start on the map The Crossroads
hill400_defend ... Start on the map The Battle For Hill 400
hill400_assault ... Start on the map Rangers Lead The Way
bergstein ... Start on the map Bergstein
breakout ... Start on the map The Brigade Box
newvillers ... Start on the map The Tiger
rhine ... Start on the map The Crossing Point

Submitted by krishnan.rajagopal

Retail Version Developer 2 Cheat. Enable the console via the "Main Menu" and clicking on "Options", then "Game Options" and click until "Yes" is displayed. Exit and get back to the "Main Menu".

Type the tilde symbol (upper case character to the left of the numeric 1 key on the keyboard). Then strike ENTER and the console will be displayed.

Input developer 2 and strike ENTER. In the bottom left corner of the "Main Menu" a new button labeled "Load" will appear. Type the tilde symbol and hit ENTER again to end the console.

Either "Load" a saved/completed scenario/map via the "Load" button or select a mission from the "Mission Select" Menu. You can also select "Resume Game". Once you are in the map/scenario at the point that you want to use cheats, i.e., you have picked up the weapons that you will end the scenario with, you can enable the console and type "give ammo" which will give you a full load of ammo for the weapons that you have in your possession and also grenades, whether you have them or not. As in the other versions of "Call of Duty" for PC, you cannot pickup any other weapons. Also anywhere in the scenario/map you may enter any of the other cheat codes that you would under "deveoper 2" already submitted by someone else.