First create a Half-Life game shortcut on your desktop (if you don’t have one). Right click on it, go to Properties, then add the line ‘-console’ to the target box so that it reads something like this: C:GamesHalf-Lifehl.exe -console

Then open the game and press ~ to lower the console, and enter sv_cheats 1. Do a quicksave, then quickload, or simply load a different level if the cheats seem to have no effect. These cheats tested on the CD version of Half-Life:

Code
god
noclip
notarget
impulse 101
sv_gravity 100
sv_gravity 800
give [item or monster name]
 Effect
Turns you invincible, on/off
Lets you fly through walls, on/off
Enemies don’t notice you, on/off
Gives you every weapon with full ammo
Set very low gravity.
Set normal gravity.
Gives you an item or monster. See below for lists.

Item Names

Code
weapon_crowbar
weapon_9mmhandgun
weapon_357
weapon_mp5
weapon_shotgun
weapon_crossbow
weapon_rpg
give weapon_gauss
give weapon_egon
give weapon_hornetgun
give weapon_handgrenade
give weapon_satchel
give weapon_tripmine
give weapon_snark
give ammo_9mmclip
give ammo_357
gives ammo_buckshot
give ammo_9mmbox
give ammo_ARgrenades
give ammo_crossbow
give ammo_rpgclip
give ammo_gaussclip
give item_suit
give item_healthkit
give item_longjump
give item_airtank
 Effect
Gives you the old crowbar.
Gives you the pistol.
Gives you the 357 revolver.
Gives you the MP5.
Gives you the shotgun.
Gives you the crossbow.
Gives you the rocket launcher.
Gives you the Guass Gun.
Gives you the Egon Gun.
Gives you the Hornet Gun.
Gives you Grenades.
Gives you the Satchel charge.
Gives you the Tripmine.
Gives you Snark bugs.
Gives you pistol clip.
Gives you 357 bullets.
Gives you shotgun shells.
Gives you MP5 clip.
Gives you M203 grenades.
Gives you crossbow bolts.
Gives you an RPG rocket.
Gives you Gauss / Egon ammo.
Gives you the HEV suit (adds game interface).
Gives medkit.
Gives you long jump upgrade (press Ctrl+Space)
Gives you the air tank upgrade.

 

Monster Names

Code
give monster_alien_controller
give monster_alien_grunt
give monster_alien_slave
give monster_apache
give monster_barnacle
give monster_barney
give monster_bigmomma
give monster_bullchicken
give monster_cockroach
give monster_gargantua
give monster_gman
give monster_headcrab
give monster_houndeye
give monster_human_assassin
give monster_human_grunt
give monster_ichthyosaur
give monster_leech
give monster_miniturret
give monster_nihilanth
give monster_osprey
give monster_scientist
give monster_sentry
give monster_snark
give monster_tentacle
give monster_zombie
 Effect
Spawns Alien Controller
Spawns Alien Grunt
Spawns Alien Slave
Spawns AH-64 Attack Helicopter
Spawns Barnacle
Spawns Security Guard
Spawns Gonarch
Spawns Bullsquid
Spawns a harmless cockroach.
Spawns Garg.
Spawns G-Man.
Spawns Headcrab.
Spawns Houndeye
Spawns Assassin.
Spawns Grunt (human soldier).
Spawns Ichthyosaur (water creature).
Spawns Leech (water creature).
Spawns Ceiling Turret.
Spawns Nihilanth,
Spawns Osprey Helicopter.
Spawns Scientist.
Spawns Stationary Turret.
Spawns Snark.
Spawn Tentacle.
Gives Zombie.