To enable the cheats, you have to start the game in console mode. So right-click the Half-Life icon in the programs menu and select properties. Here change the command to hl.exe -dev -console and start the game. To enter the console mode, press the ~ (tilde) key and type in these codes:

Effect Code


Instant Weapons, Ammo, and Armor impulse 101
Invincibility /god
Gives you some health. give item_healthkit
No clipping (walking through walls) noclip
Invisibility notarget


Gives you the crowbar. give weapon_crowbar
Gives you the glock pistol. give weapon_9mmhandgun
17 ammo for the glock pistol. give ammo_9mmclip
Ammo for the glock pistol. give ammo_9mmbox
Gives you the 357 Magnum give weapon_python
Gives you the 357 Magnum. give weapon_357
Ammo for the 357 Magnum. give ammo_357
Gives you the MP5. give weapon_mp5
Gives you primary ammo for the MP5 give ammo_9mmAR
Gives you the secondary ammo for the MP5 give ammo_ARgrenades
Gives you the secondary ammo for the MP5 give ammo_mp5grenades
Gives you the shotgun. give weapon_shotgun
Shotgun ammo. give ammo_buckshot
Gives you the crossbow. give weapon_crossbow
Crossbow ammo. give ammo_crossbow
Gives you the RPG. give weapon_rpg
Gives you ammo for the RPG give ammo_RPGclip
Gives you the egon. give weapon_egon
Gives you ammo for the Egon give ammo_Egonclip
Gives you the hornet gun. give weapon_hornetgun
Gives you the Gauss rifle. give weapon_gauss
Gives you ammo for the Gauss give ammo_Gaussclip
Gives you some hand grenades. give weapon_handgrenade
Gives you a Satchel charge give weapon_satchel
Gives you some laser tripmines. give weapon_tripmine
Gives you some snarks. give weapon_snark


Gives you the HEV suit. give item_suit
Eliminate Shadows r_fullbright 1 (Replace 1 with 0 to turn them back on.)
Set Gravity Level sv_gravity # (Lower numbers gives less gravity, higher gives more. Normal is 800.)
Spawn Marines impulse 76
Third Person chase_active 1
Third Person View thirdperson
Gives you the Long Jump Module give item_longjump
Spawn Gibs impulse 102
While looking at a monster, displays stats. impulse 103
Lists global entities impulse 104
Enemies can't hear you impulse 105
While looking at an object, displays model/sprite stats. impulse 106
While looking at an object, displays the texture name. impulse 107
Control onscreen monsters (may not work in versions of the game). impulse 109
Displays AI node information impulse 195
Creates blood infront of you, like spray paint. impulse 202
Delete Targeted Enemy impulse 203

Teleport to level

Enable the console (see above) and type "map x", where x represents the name of the level as listed below (eg.type "map c0a0" for the first level). Often you won't start where you would if you accessed the map normally. You can use No Clipping Mode to move there.

Black Mesa Inbound c0a0, c0a0a, c0a0b, c0a0c, c0a0d, c0a0e
Anomalous Materials c1a0, c1a0a, c1a0b, c1a0d, c1a0e
Unforeseen Consequences c1a0c, c1a1, c1a1a, c1a1b, c1a1c, c1a1d
Office Complex c1a2, c1a2a, c1a2b, c1a2c, c1a2d
We've Got Hostiles c1a3, c1a3a, c1a3b, c1a3c, c1a3d
Blast Pit c1a4, c1a4b, c1a4d, c1a4f, c1a4g, c1a4i, c1a4j, c1a4k
Power Up c2a1, c2a1a, c2a1b
On a Rail c2a2, c2a2a, c2a2b1, c2a2b2, c2a2c, c2a2d, c2a2e, c2a2f, c2a2g, c2a2h
Apprehension c2a3, c2a3a, c2a3b, c2a3c, c2a3d, c2a3e
Residue Processing c2a4, c2a4a, c2a4b, c2a4c
Questionable Ethics c2a4d, c2a4e, c2a4f, c2a4g
Surface Tension c2a5, c2a5a, c2a5b, c2a5c, c2a5d, c2a5e, c2a5f, c2a5g, c2a5w, c2a5x
"Forget About Freeman!" c3a1, c3a1a, c3a1b
Lambda Core c3a2e, c3a2, c3a2a, c3a2b, c3a2c, c3a2d, c3a2f
Xen c4a1
Gonarch's Lair c4a2, c4a2a, c4a2b
Interloper c4a1a, c4a1b, c4a1c, c4a1d, c4a1e, c4a1f
Nihilanth c4a3
Conclusion c5a1