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:
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)