Press [Ctrl]+[Alt]+[~] to access the console. Write com_allowConsole 1 to be able to lower the console just with "~" and then enter the following codes:

noclip - No clip
notarget - Invisibility
freeze - Freeze everything
doomhell - Jump to the last level
give all - All weapons and ammo
give doom95 - Load the '95 version of Doom
give keys - All keys
give pda - PDA
give weapon_bfg - BFG
give weapon_shotgun - Shotgun
give weapon_chainsaw - Chainsaw
give weapon_plasmagun - Plasmagun
give weapon_machinegun - Machinegun
give weapon_rocketlauncher - Rocket launcher
god - God mode
benchmark - Game benchmark
com_showfps 1 - Show FPS
timedemo demo1.demo - Benchmark test
aviDemo - Saves a demo of your playing to an AVI movie file
gfxinfo - Graphics card infomation
status - Shows game status
r_gamma [0-3] - Set gamma level
r_brightness [number] - Set brightness level
s_volume_db [number] - Set sound volume (default is 0)
s_showlevelmeter 1 - Toggle sound level display (use 0 to disable this code)
g_showprojectilepct 1 - Toggle hit % to HUD (use 0 to disable this code)
killmonsters - Kill all monsters
kill - Suicide
quit - Quit game Powered by Coranto [an error occurred while processing the directive]