Cheat Codes:
Note: These codes apply to the demo version only.

At the main menu screen of the demo enter the "Game Options" and Enable the Console. From there, push your tilde (~) button to bring down the console and type the following:

seta thereisacow "1337"

followed by

spdevmap eldaba

This will start the demo level with devmap and cheats enabled. This allows you to use any of the commands in game without restriction. When in game, bring down the console and enter any of the commands from below to activate the 'cheat':

noclip - Walk / Fly through walls
jump_height 128 - Moon jump (jump_height 39 for default)
timescale .25 - Slow motion (timescale 1 for default)
give all - Each time it's entered you'll be given 2 different weapons from the demo
god - Infinite health
notarget - Enemies ignore you
give ammo - Refill your ammunition / grenades

Cheat Mode:
Select "Game Options" at the main menu, then choose the option to enable the console. Press ~ to display the console window then enter developer 1 as a command to enable cheat mode. The "Load" button will now appear. Click it and select the desired level. After the level loads, press ~ to display the console window again, then enter devmap as a command. Press ~ during game play to display the console window.

Effect - Code:
God mode - god
Refill ammunition and grenades - give ammo
All weapons, full ammo, health and armor - give all
No clipping mode - noclip
Ignored by enemies - notarget
Suicide - kill
Spawn indicated item - give [item name]
Flight mode - ufo
Teleport to a node - jumptonode
Level select - map [level name]
Mission set select - /seta [mission set name]

Mission set names:
Use one of the following entries with the /seta code to unlock the corresponding set of missions:

Crossing The Rhine: mis_10 9
D-Day: mis_07 9
Fortress Stalingrad: mis_04 9
Hill 400: mis_09 9
Not One Step Backwards!: mis_03 9
Rommel's Last Stand: mis_06 9
The Battle For Caen: mis_08 9
The Battle Of El Alamein: mis_02 9
The Tank Squadrons: mis_05 9
The Winter War: mis_01 9

Play any mission:
Bring down the console in game with your tilde key (~) and enter the following to play your desired mission. This will allow you to play missions you are yet to unlock.

Cheat - Effect:
map rhine - Play "The Crossing Point"
map cityhall - Play "Stalingrad City Hall"
map downtown_sniper - Play "Comrade Sniper"
map libya - Play "Crusader Charge"
map 88ridge - Play "88 Ridge"
map toujane_ride - Play "Armoured Car Escape"
map toujane - Play "Retaking Toujane"
map matmata - Play "Assault On Matmata"
map duhoc_assault - Play "The Battle Of Pointe Du Hoc"
map duhoc_defend - Play "Defending The Pointe"
map silotown - Play "The Silo"
map beltot - Play "Prisoners Of War"
map crossroads - Play "The Crossroads"
map hill400_defend - Play "The Battle For Hill 400"
map hill400_assault - Play "Rangers Lead The Way"
map bergstein - Play "Bergstein"
map breakout - Play "The Brigade Box"
map newvillers - Play "The Tiger"
map downtown_assault - Play "Downtown Assault"
map trainyard - Play "Railroad Station No. 1"
map tankhunt - Play "Repairing The Wire"
map eldaba - Play "The End Of The Beginning"
map elalamein - Play "El Alamein"
map decoytown - Play "Holding The Line"
map decoytrenches - Play "The Diversionary Raid"
map demolition - Play "Demolition"
map moscow - Play "Red Army Training"

Unlock any mission:
The following cheats will allow you to unlock any mission of your choosing in the mission select screen. Bring down the console with the tilde key (button to the left of "1") in game and type the following commands to unlock your desired mission sets.

Cheat - Effect:
/seta mis_06 9 - Unlock "Rommel's Last Stand" Mission Set
/seta mis_07 9 - Unlock "D-Day" Mission Set
/seta mis_08 9 - Unlock "The Battle For Caen" Mission Set
/seta mis_09 9 - Unlock "Hill 400" Mission Set
/seta mis_10 9 - Unlock "Crossing The Rhine" Mission Set
/seta mis_05 9 - Unlock "The Tank Squadrons" Mission Set
/seta mis_04 9 - Unlock "Fortress Stalingrad" Mission Set
/seta mis_03 9 - Unlock "Not One Step Backwards!" Mission Set
/seta mis_02 9 - Unlock "The Battle Of El Alamein" Mission Set
/seta mis_01 9 - Unlock "The Winter War" Mission Set