Cheat mode
Load a game using the command line: hl.exe -dev -toconsole. Then, press ~ if the orange text on the screen does not show. While playing, press ~ to display the text prompt and type in sv_cheats 1. Then press ~ and type in one of the console commands below to activate the desired cheat.

1. Select a map name from the list below.
2. Select an item name from the list below.

Map name list

Single player
c0a0
c0a0a
c0a0b
c0a0c
c0a0d
c0a0e
c1a0
c1a0a
c1a0b
c1a0c
c1a0d
c1a0e
c1a1
c1a1a
c1a1b
c1a1c
c1a1d
c1a1f
c1a2
c1a2a
c1a2b
c1a2c
c1a2d
c1a3
c1a3a
c1a3b
c1a3c
c1a3d
c1a4
c1a4b
c1a4d
c1a4e
c1a4f
c1a4g
c1a4i
c1a4j
c1a4k
c2a1
c2a1a
c2a1b
c2a2
c2a2a
c2a2b1
c2a2b2
c2a2c
c2a2d
c2a2e
c2a2f
c2a2g
c2a2h
c2a3
c2a3a
c2a3b
c2a3c
c2a3d
c2a3e
c2a4
c2a4a
c2a4b
c2a4c
c2a4d
c2a4e
c2a4f
c2a4g
c2a5
c2a5a
c2a5b
c2a5c
c2a5d
c2a5e
c2a5f
c2a5g
c2a5w
c2a5x
c3a1
c3a1a
c3a1b
c3a2
c3a2a
c3a2b
c3a2c
c3a2d
c3a2e
c3a2f
c4a1
c4a1a
c4a1b
c4a1c
c4a1d
c4a1e
c4a1f
c4a2
c4a2a
c4a2b
c4a3
c5a1

Multiplayer/Deathmatch
boot_camp
bounce
datacore
lambda_bunker
snark_pit
stalkyard
subtransit
undertow

Hazard course
t0a0
t0a0a
t0a0b
t0a0b1
t0a0b2
t0a0c
t0a0d

Item name list

item_airtank
item_antidote
item_battery
item_healthkit
item_longjump
item_security
item_sodacan
item_suit
ammo_357
ammo_9mmAR
ammo_9mmbox
ammo_9mmclip
ammo_ARgrenades
ammo_buckshot
ammo_crossbow
ammo_egonclip
ammo_gaussclip
ammo_glockclip
ammo_mp5clip
ammo_mp5grenades
ammo_rpgclip
weapon_357
weapon_9mmAR
weapon_9mmhandgun
weapon_crossbow
weapon_crowbar
weapon_egon
weapon_gauss
weapon_glock
weapon_handgrenade
weapon_hornetgun
weapon_mp5
weapon_python
weapon_rpg
weapon_satchel
weapon_shotgun
weapon_snark
weapon_tripmine
weapon_quantumdestabilizer

Cheat mode (alternate)
Start a game using one of the command line parameters below to activate the desired cheat.

Monster creation
You have to be within the loading area of the desired monster for this cheat. For example, you cannot load up Barney while your fighting the Nihilanth. Type in give <monster name> and the matching monster will appear. Note: Also activate the /noclip first, or you will be stuck inside the monster.

People
monster_human_grunt
monster_barney
monster_scientist
monster_generic
monster_gman

Monsters
monster_sentery
monster_headcrab
monster_alien_slave
monster_alien_grunt
monster_bullchicken
monster_zombie
monster_apache
monster_ichthyosaur
monster_bigmomma
monster_barnacle
monster_tentacle
monster_gargantuan
monster_nihilanth
monster_houndeye
monster_rat
monster_cockroach
xen_tree
xen_spore_small
xen_spore_medium
xen_spore_large

Corpses
monster_barney_dead
monster_scientist_dead
monster_hevsuit_dead

Key binding
In order to activate codes easier, bind them to keys. Here is an example, type /bind v "impulse 101" at the console window to bind the "HEV suit, weapons, and ammo " code to the "V" key.

Chat key bindings
You can type in bind "p" "say Hello" or bind "p" "teamsay i need backup" and press [Enter] when your at the console window to bind those and other chat commands.

Zoom on every weapon
Obtain the Crossbow in single player mode and save with the weapon that you want to zoom in with. Then change to the Crossbow and zoom in, then quick load and your other weapon will now be zoomed in. You can now change weapons and they will all be zoomed in. To get out of zoom, switch back to the Crossbow and press the second fire button until it zooms out.

Hints & Tips

HEV suit falls out
First enable the /impulse 101 code while your in mid-air and an error saying the hev suit has fallen out will be shown.

Starting tips
After the "accident", you will find a scientist giving CPR to a security guard. Now wait 15 to 20 seconds to see the outcome, which will results in the security guard being revived. He is not useful at this time, but go back to him after getting the crowbar. Now kill him with the crowbar so he can not fire back to obtain his gun and ammunition.

The beginning of the game also has a glitch. There is a scientist sitting in front of a broken instrument panel, in the area of the first scientist who opened a door for you. This scientist is invincible. You can shoot or beat him using a crowbar, and all he will do is whine. This will also saturates the area with a lot of blood.

Soon after this, you will ride an elevator that goes up. Also have the gun ready. Shoot the monster attacking the security guard a few of the shots should do it. This security guard can cover you until you get to the main entrance area.

One important tactic in the early game is to use your "allies" to your advantage. When you no longer need the services of a security guard, kill him and grab his ammunition. A scientist is also useful in drawing some enemy attack. Just be careful not to harm an ally when another security guard is there, as he will attack you. Also be aware that monsters can sense your allies; and even if you crawl, monsters can hear your allies' walk.

Completing We've Got Hostiles quickly
As soon as you go into the "We've Got Hostiles" level, turn to your right and use the /noclip code to simply float through the glass window with the security guard being eaten by a zombie. When you are in there, press the switch that will open the Silo and the Silo door will open. Now float back out of the room, disable the noclip code, then go through the Silo door to start the next level.

Beating Gargantua
You can kill Gargantua when you meet him again in the parking lot. As you walk into the parking lot in the Incoming section of the game unload all your missile launcher ammunition, six grenades, and four Tau Cannon charged shots and how clip from a combat rifle to kill him.

Using the pistol
Use this trick to save ammo for every gun other than pistol. Most creatures or persons can be killed with five or less direct shots of the pistol.

Crabs: 2 shots or 1 crowbar hit
Zombies: 4 shots
Electric Aliens: 3 shots
Trip Bomb: 1 shot
Machinegun on stand: 5 shots
Soldiers: 5 shots
Dogs: 3 shots
Spitters: 4 shots

Using guards
If you have a guard, get him close to you and he will take care of almost anything for you. The only time you will need to fire is if the creature is close to the guard.

Rocket
When your in the "Apprehension" level, you will come to a part where you go through two red doors reading "CAUTION" that lead into an area with a sunken in area, two military officers, and a turret gun. First kill the two officers. Then, turn and face the direction opposite the wall with the door and the window. Now enable the "No Clipping" code and walk forward through the natural wall. You will see a yellow shaft. When you get near it, you will see a huge rocket inside.

Advance to final Boss
Just enable the console window and go to the Hazard course. When you get to the bridge to obtain hazard suit, jump of it into the sludge. You should be teleported to Nihilanth.

Saving ammunition
Do not waste pistol ammo on headcrabs. Just use your crowbar, as it is more useful.

Spawn Grunts
Simply enable cheat mode, then use the /impulse 76 code to activate the Grunt-O-Matic. A message to start a new game in order for it to work will be shown. If you want to continue where you are at, quicksave, then quickload the game. When you have quickloaded, type in the code again to spawn a Grunt. Note: You need to use the /nocliping code before you spawn the grunt because he will be spawned near you. If this is not done, a message stating that the monster spawned is stuck in a wall may appear and the game will end. Do not spawn the Grunt in a closed position or the same message will be shown. The Grunt you spawn will see you as a hostile. To have more fun, use the /notarget code and spawn a number of grunts to do your alien hunting.

Fun with spawning
Simply enable cheat mode, then use the entities code to get a list of the creatures in the spot you are currently in. Normally, when you try to spawn a creature, you have to use the noclip code to levitate in the air and spawn the creature near any objects. If a part of a spawned creature is spawned inside a wall, ceiling, or another creature, the game crashes. But if you enable the developer 0 code, the game continues even if a spawned creature is stuck, but the creature will have yellow dots around it. Also, bind the spawn commands to unused keyboard keys; for example bind X "impulse 76" or bind y "give monster_scientist". The impluse 76 code will work everywhere, and the hostile grunts created with it are easy to place where you want as they will appear in front of you, rather than above. Then enable the noclip code and fly around by pressing the bound keys. Now watch as Barney's Aliens and Grunts battle it out while Scientists run around being killed.

Grunt smell comment
When your in the first level, enable the /impulse 101 code and go to either one of the two security officers guarding an area. Now use the /impulse 76 code to spawn a Grunt close to them. Do not spawn the Grunt in a wall or Barney or the game will end with an error message. Now kill the Grunt fast and leave it on the floor for a few seconds. Now Barney should say "Ew, what's that stench?" or something similar.

More powerful shotgun
When your using the shotgun, right click to shoot two shots at once. This will kill everything twice as fast.

Soft landings
If you do jump or fall from a high spot, use the Tau Cannon Gun. When you fall, use secondary fire to hold it and release it before you hit the ground. You will land without the loss of any health. You can use this method to get to high places by doing this from the ground.

Barney gets cut in half
When you go into the room where the lasers are shooting out the walls, run through the room. There should be a Barney on the floor. Watch carefully and you can see the laser go across and cut him in half.

Spawn Barney in War with Nihilanth
Normally when you want to spawn Barney at the Nihilanth episode, you will receive an error message. To solve this, go to Lamba Core teleport to Xen. Then enable the /noclip code. After the scientist finishes his teleport to Xen, go through and dark. Then, type give monster_barney constantly until you arrive. You will reach a strange island and not have a Barney, but you have to type it. After that, you can play and fight with Barney on the alien world. You also can do this at Nihilanth teleports.

Exploding scientists
When your on the level where you are picking up your HEV suit before the accident, use the /impulse 101 code and select the crowbar. Now walk up to a scientist and wait for him to do a scripted event like scratching his chin while looking at computer readings. Keepon hitting him with the crowbar. When the scripted event is done, depending on how many times you hit him, there will be an explosion of meaty chunks.

Freeman's locker
When you start a game and get your suit, look at the lockers. There will be marked "Freeman". Now walk straight to it and you will see a photo of his little boy or girl.