Unreal

Cheat mode:
Press [Tab] or ~ to display the console window. Then, enter one of the following codes to activate the corresponding cheat function.

Effect	Code
Full ammo for current weapon	allammo
Full ammo for all weapons in inventory	allammo 999
Flight mode	fly
No clipping mode	ghost
Disable flight and no clipping modes	walk
Invincibility for current level	god
Add weapon or item to the world1	summon <item name>
Toggle time	playersonly
Jump to indicated map2	open <map name>
Third person view	behindview 1
First person view	behindview 0
Set game speed2	slomo<0.0-10.0>
Kill monsters	killpawns
Kill all bots (multiplayer)	killpawnsbot
Kill all of indicated enemy type	killall <enemy name>
Invisibility	invisible
Spawn indicated number of bots	addbots <number>
Broadcast message to other players	say <text>
Cannot drown	amphibious
Suicide	suicide
Preferences menu	preferences
Play dead	feigndeath
Unlimited charge for selected item	set <item> charge 9999999999
Reset graphics and textures	flush
Toggle game pause	pause

1. Set <item name> according to the following list.
2. Set <map name> according to the following list.
3. Set <number> to 1.0 for normal speed.

JONTONKON and josh moses.

eightball
flakcannon
stinger
sheildbelt
juicebox
amplifier
scubagear
jumpboots
kelvarsuit
armor
dispersionpistol
automag
ASMD
razorjack
gesbiorifle
nali
translator
minigun
rifle
dampener
flare
flashlight
forcefield
invisibility
jumpboots
searchlight
nalifruitseed
voicebox
bandages
nalihealingfruit
superhealth
armor
asbestossuit
antitoxinsuit
slith
mercenary
krall
brute
titan
dispersionpowerup1
dispersionpowerup2
dispersionpowerup3
dispersionpowerup4

Creature names:
Use the following values with the summon code. Note: Some of these creatures may not summon unless you are in a Return to Na Pali area.
Randy Rockholt.

Brute
Cow
Devilfish
Fly
Krall
Krallelite
Lesserbrute
Manta
Mercenary
Mercenaryelite
Nali
Predator
Pupae
Skaarjberserker
Skaarjgunner
Skaarjinfantry
Skaarjlord
Skaarjofficer
Skaarjwarrior
Skarrjscout
Skarrjtrooper
Slith
Spinner
Tentacle
Warlord

The following creatures can only be summoned while in Ghost mode.
Randy Rockholt.

Titan
Stonetitan
Gasbag
Giantgasbag
Behemoth
Queen

Map names:
Use the following values with the open code.
josh moses.

Bluff
Ceremony
Chizra
Dark
Dasacellars
Dasapass
Dcrater
Dig
DKNightOp
DMARIZA
DMCURSE
DmDeathFan
DmDeck16
DMElsinore
DMfith
DmHealPod
DmMorbias
DmRadikus
DmTundra
Dug
Endgame
Entry
ExtremeLab
ExtremeEnd
ExtremeGen
ExtremeBeg
ExtremeCore
ExtremeDark
ExtremeDGen
Gateway
Harobed
IsvDeck1
IsvKran4
IsvKran32
NaliBoat
NaliC
NaliLord
Noork
NyLeve
Passage
QueenEnd
Ruins
SkyBase
SkyCaves
SkyTown
SpireVillage
TerraLift
Terraniux
TheSunspire
Trench
Unreal
VeloraEnd
Vortex2

Less gore:
Note: This procedure involves editing a game file; create a backup copy of the file before proceeding. Use a text editor to edit the "unreal.ini" file in the "\unreal\system" folder. Find the entries under [Engine.GameInfo] heading, which appear as:

[Engine.GameInfo]
bLowGore=False
bVeryLowGore=False

Changing the value of "bLowGore" to "True" will stop the bodies from exploding when hit too hard. They will just disappear instead of flying to pieces. Changing the value of "bVeryLowGore" to "True" changes the blood splatters from red to green when you shoot something.
Albert Brown.

Hint: Quadshot gun:
This is an extra gun on the game. Enable the summon quadshot code and a different gun will appear. Pick it up. If you have the stinger gun, take it out and press 3 again. if you do not have the stinger, press 3 and a gun will appear, taking up almost all of the screen and looks like a plus sign. The gun has no ammunition and will not shoot.
Sean Palka.

Hint: Hidden area at end:
Go to the ending scene (use the open endgame code if desired), and enable the ghost code. Follow the same path that the rocket would travel until you get to the darkness at the end (before the rocket goes outside). Go into the darkness and look around. You should see what appears to be a black box with a yellow border, and a light switch on top.
Eric Goodwin.

Hint: Hidden photograph (Game Of The Year Edition):
In the Codex Of Wisdom map, go to the location with the Biosludge and ammunition. Between those two is a hole. Fall down and face the wall. Enable the ghost code and walk through the wall. There is a photograph of a man with the caption "Pretty fly...".
Edwin Ireson.

Hint: Hidden room:
Go to the extreme dark level in botmatch (or enable the summon extremedark code). Enable the ghost code at the start of the level. Fly to the lowest room in the area. There is no way to get in or out of this room without the ghost code.
fart twice.

Hint: Enemy versus enemy:
To get two of your enemies to fight, get behind one so that the other hits or shoots the first one. Then, step back and they will start fighting each other. They will fight until one kills the other, then it will turn its attention back on you.
fart twice.

Go to Botmatch, then Coop Game. From here, you can pit creatures spawned with the summon code against each other in whatever instance of the game you desire. There are two ways to get the creatures to fight each other until one dies. The most effective method is to enable the fly and invisible codes then summon the desired creature. Then, right click to fly directly above the creature you just summoned. Once you are above the summoned creature, summon another creature of your choice. That creature will fall on the creature below him, and they will begin fighting until one of them dies. Note: This does not work on creatures of the same species, for example a Krall falling on top of another Krall.
Randy Rockholt.

Killing the "Stone Titan" Mario-style:
In the "Velora Pass" map, after Skaarj Outpost 3J and before Bluff Eversmoking, you must fight a Titan that is stronger than any other. Retrieve the Dispersion Pistol power-up from the plate in front of its throne. It comes to life and the bridge to the next level drops into a lava-filled chasm. You are supposed to kill it and stand on its chair to make the bridge rise again in order to continue. However, this can be done in a satisfyingly retro way, without firing a shot. Instead of wasting your firepower on it, lure the Titan around towards the back of the structure that its throne is mounted in. It is a stupid creature and will follow you, albeit slowly. Run quickly around to the front, step on the plate in the seat of the throne, and dodge the Titan until the bridge is high enough to cross. Proceed across the bridge and hide around the corner (after luring the Titan back into your field of view if necessary), popping out every now and then to ensure it is still following, dodging boulders as necessary. Wait until the Titan is far enough onto the bridge so that it cannot turn back fast enough. Quickly run up and hit the lever on the right-hand bridge support. The bridge will fall and after a short while the Titan will die. The lava causes incremental damage; at least five "hits" from the lava is needed to kill it. You will know that it is dead when the ground stops shaking. Hit the lever again to raise the bridge and survey your handiwork if desired; either way the door to the next level is now open.