Press "~" to open the console and enter one of the following commands: 
 
god - Toggle God mode 
version - Return game version 
map - Load another map (see further on for possible maps) 
mapcomplete - Mark the map as completed (putting you at the next map) 
noclip - Toggle walking through obstacles 
respawn - Toggle monster from respawn 
monster - Turn monsters off 
developer - Toggle developer mode 
record - Start recording a demo 
stoprecord - Stop recording a demo 
play - Play a recorded demo 
stopplay - Stop playing a recorded demo 
musictrack - Change the current playing musictrack 
prestrack - Last music track played 
drawface - Toggle drawing of texture faces 
drawtris - Draw the map sections 
drawgun - Toggle the drawing of weapons held 
drawone - ? 
drawportal - Toggle Outlining of portals and doors 
drawnormal - toggle Draw wall normals 
pview - Toggle 3rd person or static view 
drawbound - Toggle highlighting of bound objects 
drawcell - Toggle highlighting of individual cells 
fov - Change the field of view 
jumpstep - Change the jumpstep value 
groundacc - Accelleration speed on ground 
groundslow - Slowing speed on ground 
gravity - Gravity 
exit - Quit the game 
maxspeed - Maximum moving speed 
airacc - Acelleration in the air 
airslow - Slowing in the air 
soundsys - change current used sound system 
bombslow - Speed at which bombs slow 
musicvol - Ingame music volume 
soundvol - Ingame sound volume 
autoswitch - Toggle autoswitch weapons mode 
fullscreen - Toggle between full screen or windowed mode 
colordepth - Change the current bitdepth 
videomode - Change the current videomode 
bms - Change bms? 
bmd - Change bmd? 
statutbar - Toggle the HUD display 
animspeed - Animation speed 
lightmap - Toggle lightmapping 
cullface - Toggle backface culling 
renderent - Toggle rendering of entities 
directstart - Toggle direct start? 
eps - Change eps? 
offset - Change offset? 
leaf - Change leafs? 
noscript - Toggle the scripting in the engine on or off 
resetgame - Reset internal game state 
saveconfig - Save current config to file 
loadconfig - Load config from file 
picmip - Change amount of offset pixels during mipmapping 
gamma - Change gamma 
drawfsp - Show framerate, set to 1 to turn on 
invertmouse - Invert mouse control 
cvel - Change cvel? 
pvel - Change pvel? 
prvel - Change prvel? 
plook - Change plook? 
killdepla - Amount of Depla's killed 
killmorba - Amount of Morba's killed 
killzeubat - Amount of Zeubat's killed 
killsubzerat - Amount of Subzerats killed 
killzemummy - Amount of Zemummy killed 
 
Possible maps to use with the commands are: 
 
h1m0 
h1m1 
h1m2 
h1m4 
h1m5 
h1m6 
h1m7 
h1m8 
h1m9 
mapbonus1 
mapbonus2