1. Enter the Steam control panel then select the "My games" tab.
2. Right Click the "Left 4 Dead 2 Demo" option then select "Properties".
3. Select "Set Launch options" then enter -console and accept it.
4. Start the game, and the console window should now appear.
5. Enter bind p toggleconsole as a console command. Click and close the
console window and start a single player game.
6. Press "P" during game play to display the console window, then enter
sv_cheats 1 to enable cheat mode.
If the message "Can't use cheats now; please exit to main menu and start your
own listen
server with "map mapname" so that you could enable cheats." appears, enable the
map c5m1_waterfront or map c5m2_park code. You will return to the main menu.
Enable either map code again, then enable the sv_cheats 1 code again.

 You can now enter one of the following codes.

Effect                             Code

Toggle God mode for entire team  - god [0 or 1]
Gain health                      - give health
Defibrillator                    - give defibrilator
Adrenaline                       - give adrenaline
First aid kit                    - give first_aid_kit
Pain Pills                       - give pain_pills
Commit suicide                   - kill
Quit game                        - quit
Toggle no clipping mode          - noclip
Toggle Incendiary Ammo upgrade   - upgrade_add incendiary_ammo
Toggle Explosive Ammo upgrade    - upgrade_add explosive_ammo
Toggle Laser Sight upgrade       - upgrade_add laser_sight
Grenade launcher                 - give weapon_grenade_launcher
Hunter claws                     - give melee
Combat rifle                     - give rifle_desert
AK-47                            - give rifle_ak47
Sniper rifle                     - give sniper_military
Magnum                           - give pistol_magnum
Silenced SMG                     - give smg_silenced
Chrome shotgun                   - give shotgun_chrome
SPAS shotgun                     - give shotgun_spas
Nightstick                       - give tonfa
Boomer Bile                      - give vomitjar
Guitar                           - give electric_guitar
Frying pan                       - give frying_pan
Machete                          - give machete
Double pistol                    - give pistol
Pump shotgun                     - give pumpshotgun
Auto shotgun                     - give autoshotgun
SMG                              - give smg
M16                              - give rifle
Sniper rifle                     - give hunting_rifle
Molotov cocktail                 - give molotov
Pipe bomb                        - give pipe_bomb
Propane tank                     - give propanetank
Gas can                          - give gascan
Oxygen tank                      - give oxygentank
Refill ammunition                - give ammo
Toggle unlimited ammunition      - sv_infinite_ammo [0 or 1]
Spawn Spitter                    - z_spawn spitter
Spawn Jockey                     - z_spawn jockey
Spawn Charger                    - z_spawn charger
Spawn common zombie              - z_spawn zombie
Spawn zombie mob                 - z_spawn mob
Spawn Boomer                     - z_spawn boomer
Spawn Hunter                     - z_spawn hunter
Spawn Witch                      - z_spawn witch
Spawn Smoker                     - z_spawn smoker
Spawn Tank                       - z_spawn tank