DOOM 3 [cheats] Bring the console up with [~] and type the following codes in to blow 
the monsters back to hell:) 

aviDemo = Saves a demo of your playing to an AVI movie file 
benchmark = Game Benchmark 
doomhell = Skip all levels to last 
freeze = Freeze all on screen 
gfxinfo = Graphicscard infomation 
god = God mode 
noclip = No Clip 
notarget = Invisibility to most enemies 
com_drawfps 1 = Show FPS 
give all = Full load of weapons and ammo 
give doom95 = Load the '95 version of Doom 
give keys = Acquire all the keys you'll ever need 
give weapon_machinegun = Machinegun 
give weapon_shotgun = Shotgun 
give weapon_plasmagun = Plasmagun 
give weapon_bfg = BFG 
give weapon_chainsaw = Chainsaw 
give weapon_rocketlauncher = Rocket Launcher 
status = Your game status 
quit = Quid aka Exit 

Below is the rest of the codes. At the moment we don't have time to find 
out what they're all good for. Play around with them yourselves!! 

_use 
_moveRight 
_moveLeft 
_moveDown 
_forward 
_back 
_right 
_left 
_lookDown 
_lookUp 
_attack 
_moveUp 
_speed 
_strafe 
_button7 
_button6 
_button5 
_button4 
_button3 
_button2 
_button1 
_button0 
aasStats 
addarrow 
addline 
blinkline 
bindlist 
bind 
centerview 
compressDemo 
connect 
clearlights 
conDump 
clear 
cvar_restart 
cvarlist 
combineCubeImages 
crash 
collisionModelInfo 
dirtyfeet 
dir 
demoShot 
disconnect 
dmap 
echo 
envshot 
exec 
exportmodels 
editSounds 
editLight 
editor 
error 
fillrate 
flashlight 
focusSoundsEditor 
give 
game_memory 
in_restart 
kill 
killRagdolls 
killMoveables 
killMonsters 
keepTestModel 
listModels 
listSkins 
listMaterials 
listImages 
listModes 
listLightDefs 
listEntityDefs 
listMonsters 
listEntities 
listThreads 
listSounds 
listAnims 
listCollisionModels 
listlines 
listVertexCache 
map 
modulateLights 
noclip 
notarget 
nextanim 
overlayGUI 
path 
poplight 
parsewait 
printShader 
printMode 
playDemo 
playCmdDemo 
playerModel 
prevanim 
reload 
reloadSounds 
reloadSoundShaders 
reloadFx 
reloadanims 
reexportmodels 
removeline 
runReach 
runAAS 
recordCmdDemo 
recordDemo 
recordCmdDemo 
recordDemo 
renderbumpFlat 
renderbump 
roq 
reloadGuis 
reset 
regenerateWorld 
reloadImages 
reloadShaders 
reloadModels 
script 
reloadEntityDefs 
s_musictrack 
s_cacheInvalidate 
s_cacheInfo 
s_restart 
seta 
set 
spawn 
setviewpos 
setStepGamma 
setu 
sets 
sizeDown 
sizeUp 
screenshot 
spawnServer 
stopRecording 
say 
testTrace 
testImage 
testShader 
testBump 
testLight 
touchFx 
touchGui 
touchFile 
toggle 
testSIMD 
touchMaterial 
testFx 
touchSound 
listSoundShaders 
touchParticle 
testDamage 
testblend 
testanim 
testParticle 
testModel 
testWipe 
testGUI 
timeDemo 
testmap 
touchSkin 
touchModel 
unbind 
unbindall 
vid_restart 
vstr 
writeConfig 
writePrecache 
weapon 
weapnext 
where 
weapprev 
weaponSplat