Left 4 Dead Cheats

At the main menu, select "Options," then "Keyboard/Mouse." Enable "Allow Developers Console." During gameplay, press "~" to access the console. Type in "Sv_Cheats 1" and press "Enter" to enable the cheats. Then, enter any one of the following:
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god --> Invincibility

sv_infinite_ammo 1 --> Unlimited Ammunition

noclip --> Toggles No Clipping Mode

give pistol --> Get Pistol

give ammo --> Full Ammunition

z_spawn weapon_SMG --> Gives you the SMG.

z_spawn mob --> spawns a zombie horde

z_spawn --> spawns a special infected (infected names:hunter,boomer,smoker,witch,tank)

give health --> gives 100 health

give hunting_rifle --> gives hunting rifle

give molotov --> gives molotov cocktail

give autoshotgun --> Gives auto shotgun

give health --> gives full health

z_spawn tank --> Spawns tank at location of crosshair

z_spawn boomer --> Spawns boomer at location of crosshair

z_spawn smoker --> Spawns smoker at location of crosshair

z_spawn hunter --> Spawns hunter at location of crosshair

give pain_pills --> Gives pain pills

thirdperson --> Sets the camera to be in third person mode.

thirdperson_mayamode --> Sets the camera to be fixed in place while in either third person or third person shoulder mode. Enter once to turn on and enter again to turn off.

thirdpersonshoulder --> Sets the camera behind the shoulder in third person.

give rifle --> Gives you an Mk 47 (machine gun)

z_health --> Change Zombie Health

z_speed --> Change Zombie Speed

director_panic_forever 0/1 --> Enables/Disables never ending panics.

z_common_limit --> Sets the maximum amount of regular zombies

director_force_panic --> Forces a panic event

z_spawn zombie --> Spawns 1 Zombie

give first_aid_kit --> gives you first aid kit

give pipe_bomb --> gives pipebomb

give molotov --> gives molotov

give gascan --> gives gascan

give oxygentank --> gives oxygen tank

give propanetank --> gives propanetank

fire --> Spawns a lighted molotov right on the floor under you.

boom --> Spawns a active pipebomb under you.

firstperson --> Play in first person (default); this cheat is only necessary if thirdperson mode is enabled

z_frustration_lifetime <#> --> Sets the number of seconds until the player loses control of the Tank from not attacking survivors

z_tank_health <#> --> Sets the maximum health of the Tank

z_witch_damage <#> --> Sets the amount of damage a Witch's attack does.

z_witch_allow_change_victim <1/0> --> True/False setting that allows the witch to change targets instead or focus on the one survivor that alerted her first

z_witch_burn_time --> Amount of time before a burning Witch dies from fire (does not affect damage caused by fire)

thirdpersonshoulder --> Sets the camera to over-the-shoulder third person mode

director_no_mobs <1/0> --> No mob rushes

director_stop --> Shuts off all wanderers, mobs, specials, and bosses

tongue_range <#> --> (Default 750) Sets the maximum range of the smoker's tongue attack

sb_friendlyfire <1/0> --> Sets whether or not bots (and only bots) are allowed to do firendly fire damage

director_no_human_zombies 0/1 --> Disables/enables controllable Boss Infected on any map

retry --> You can unlock achievements while using cheats (after entering sv_cheats 1, enter retry so that it will restart the game with the cheats on)

At the main menu, select "Options," then "Keyboard/Mouse." Enable "Allow Developers Console." During gameplay, press "~" to access the console. Type in "Sv_Cheats 1" and press "Enter" to enable the cheats. Then, enter any one of the following:

Enable the console via the Options menu. Bring up the console and type "sv_cheats 1" to activate cheat mode. You may then type any of the following cheat codes.

Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Helping Hand (20 points): Revive 50 incapacitated Survivors.
Field Medic (20 points): Heal 25 Survivors with a first aid kit.
Pharm-assist (20 points): Give pain pills to 10 Survivors.
My Bodyguard (15 points): Protect any Survivor from an attacking Infected 50 times.
Dead Stop (10 points): Punch a Hunter as he is pouncing.
Cr0wnd (30 points): Kill a Witch with a single headshot.
Untouchables (30 points): No Survivors take damage after contacting the rescue vehicle.
Drag and Drop (20 points): Rescue a Survivor from a Smoker's tongue before he takes damage.
Blind Luck (20 points): You or another Survivor take no damage after being vomited on by a Boomer.
Akimbo Assassin (30 points): Survive an entire campaign using only pistols.
Hero Closet (10 points): Rescue a Survivor trapped in a closet.
Hunter Punter (10 points): Shove a Hunter off of a pinned and helpless Survivor.
Tongue Twister (20 points): Free yourself from a Smoker who has grabbed you with his tongue.
No Smoking Section (15 points): Kill 10 Smokers as they are pulling helpless Survivors.
101 Cremations (20 points): Set 101 Infected on fire.
Do Not Disturb (20 points): Sneak past all Witches in a campaign without disturbing one.
Man vs Tank (30 points): Single-handedly kill a Tank.
Tankbusters (20 points): Kill a Tank without it dealing any damage to a Survivor.
Safety First (30 points): Play an entire campaign with no Survivors taking friendly fire damage.
No-one Left Behind (20 points): Beat a campaign with all 4 Survivors.
Unbreakable (30 points): Finish a campaign without ever being healed.
Witch Hunter (20 points): Kill a Witch without any Survivor taking damage from her.
Red Mist (20 points): Kill 1000 Infected with a mounted machine gun.
Pyrotechnician (20 points): Blow up 20 Infected in a single explosion.
Zombie Genocidest (20 points): Kill 53,595 Infected.
Dead Giveaway (10 points): Heal a fellow Survivor when your own health is below 10.
Stand Tall (20 points): Survive a campaign without being incapacitated.
Zombicidal Maniac (30 points): Survive any campaign on Expert.
What Are You Trying to Prove? (35 points): Survive all campaigns on Expert.
Nothing Special (30 points): Survive a campaign with no Survivors taking damage from Special Infected.
Burn the Witch (10 points): Light a Witch with a Molotov.
Towering Inferno (10 points): Light a Tank with a Molotov.
Spinal Tap (10 points): Kill an Infected with a single blow from behind.
Stomach Upset (20 points): All Survivors complete a campaign without being vomited on.
Brain Salad (15 points): Make 100 headshot kills.
Jump Shot (20 points): Headshot a Hunter while he's leaping.
Mercy Killer (15 points): Survive the No Mercy campaign.
Back 2 Help (20 points): Leave a safe room to save an incapped teammate and bring them back safely.
Toll Collector (15 points): Survive the Death Toll campaign.
Dead Baron (15 points): Survive the Dead Air campaign.
Grim Reaper (15 points): Survive the Blood Harvest campaign.
Ground Cover (30 points): Save another Survivor from a Special Infected while on the ground.
Clean Kill (10 points): Shove a Boomer and then kill him without him splashing on anyone.
Big Drag (20 points): Drag a Survivor 100 feet with your tongue.
Chain Smoker (20 points): Constrict two Survivors in one life as a Smoker.
Barf Bagged (20 points): Cover four Survivors with Boomer bile at once.
Double Jump (20 points): Pounce two different Survivors in one life as a Hunter.
All 4 Dead (30 points): Kill all four Survivors in one life while playing as a Tank.
Dead Wreckening (20 points): Dole out 5000 total Survivor damage as a Special Infected.
Lamb 2 Slaughter (20 points): As an Infected, incap a Survivor who has entered and left a safe room.

To insert the cheats below, call-up the in-game cheats console by pressing the tilde (~) key. Then, insert the cheats on the left for the corresponding result on the right.