To enable Network Cheat mode, hold ALT and type "iddtiddtiddtiddt" in map mode.

Type "t" in the map to enter talk mode, then hold ALT and type "iddt" multiple times. This will reveal the entire map. Repeat the code to reveal all items. Repeating the code again will return the map to normal.

Start the game with the doom2 -turbo 250 command line to have your player in turbo for the entire game.

Type "idclev32" or "idclev31" during game play to restart in a completely new level. When you complete one of those levels you will always start on the level suburbs and continue your Doom 2 game.

Activate the following cheats by entering the corresponding codes:

CHEAT FUNCTION - CHEAT CODES
Invincibility - iddqd
All weapons, keys, ammo, and 200% armor - idkfa
Reset ammunition - idfa
Berserker strength - idbeholds
Temporary invincibility - idbeholdv
Temporary invisibility - idbeholdi
Full automap - idbeholda
Anti-radiation suit - idbeholdr
Light amplification visor - idbeholdl
Walk through walls - idclip
Chainsaw - idchoppers
Level select - idclev
Toggle full map; full map and objects; normal map - iddt
Display coordinates and heading - idmypos
Change music to indicated level - idmus

Start the game with the doom -devparm command line to activate the corresponding cheat function. Note: The parameters marked with an asterisk (*) do not require -devparm in the command line. Most of these parameters can be mixed and matched to create different effects. For example, start the game with the doom -devparm -wart 1 8 -record demo01 -respawn command line would record a demo on episode one, level eight, with monster respawn. Finally, press F1 during development mode for a 256 color screenshot in .PCX format.

CHEAT FUNCTION - COMMAND LINE PARAMETER
Read in a command line parameter file - @
Activates DeathMatch v2.0 (v1.4 and above) - -altdeath
End the game after twenty minutes - -avg
Uses C:\DOOMDATA directory for data - -cdrom
Internal development, texture mapping - -comdev
Read an alternate configuration file* - -config
Start NetDoom in Deathmatch mode* - -deathmatch
Dump debug info to debug.txt - -debugfile
Developers mode - -devparm
Start at indicated episode* - -episode <1-3>
Uses original GUS instrument mapping - -GUS
Uses new GUS instrument mapping (default) - -GUS1
Nightmare mode without respawn* - -fast
Use external PWAD file* - -file <.wad filename>
Set up a network terminal for the "left view"* - -left
Starts from indicated saved game* - -loadgame <0-5>
Set maximum size of LMP recording* - -maxdemo
Starts NetDoom with indicated player amount* - -nodes <1-4>
Internal bugging switch - -noblit
Internal bugging switch - -nodraw
Disable the joystick - -nojoy
No monsters* - -nomonsters
Disable the mouse - -nomouse
Disable background music - -nomusic
Disable sound effects - -nosfx
Disable sound - -nosound
Enable stereo music through OPL-3 on PAS16 - -opl3
Enable phase shifting on PAS16 - -phase
Play back recorded demo* - -playdemo
Record demo until you finish or die* - -record
Record a demo from saved game* - -recordfrom <0-5>
Internal development, texture mapping - -regdev
Enemies respawn in non-Nightmare* - -respawn
Set up a network terminal for "right view"* - -right
Internal development, texture mapping - -shdev
Start at indicated skill level* - -skill <1-5>
Calculates number of times screen is redrawn during a demo - -timedemo
Increases the speed of the marine - -turbo <1-255>
Warp to episode (1-3) level (1-9) - -warp <1-3> <1-9>
Load PWAD named ExMy.wad - -wart <1-3> <1-9>
Unknown - -statcopy
Unknown - -control

If you play the challenge made by the last boss backwards, you will hear him say "To win the game you must kill me, John Romero".

When you enter the room with the huge window, look along the left wall until you get to a switch. Hit the switch then get on the platform and wait for it to rise. Kill any enemies in your way. After that, click the "Open Door" button on the wall you are now facing. The wall should open. Again, clear out any enemies in your way. Go the the far end of that passageway and look toward the room. Hold [Sprint] and run off the platform and onto the lighted square. You should hear a faint noise of a door opening. Go to the room where the blue life jars were located. The door in the back of that room should have opened up to reveal a rocket launcher.

At the start of the level, do not drop the area you start at. Instead, go backwards. You should see a rail. Go towards the rail then turn right. You should see a hidden chain saw.

Once you get to the exit door (do not open it), go straight back a short distance past the imp's cage. Then, press the "Open" button on the wall, and a door will open.

Head to the lift near the end of the level, which is also used to open the rocket launcher room. Open the secret door and activate the switch, then get off the lift and walk up to the window. Walk to the right to find an opening to the outside. If playing under the Ultra Violence setting or higher there will be imps outside. There will also be a shotgun and some shells.

During the final level, Icon Of Sin, there is a giant face that keeps launching "boxes" through a hole in his forehead. You must activate the platform. Take the invulnerability just in case and, while going up, aim with the rocket launcher at the correct moment so that the rocket goes through the hole from where the boxes appear from. Repeat this as many times as needed.

You can get opposingspecies of monsters to attack each other (for instance, an Imp and a Demon).

During the last level, enable the idclip code. Go through the wall with the demon head on it. You will see that the final boss is the head of John Romero, the co-creator of the Doom series.

Toward the end of level 30 when there are no monsters, the face still shoots out monsters. Activate the idclip code and go through the same wall as "boxes" are going through. Either save your game or enable the iddqd code. There are thousands of monsters to kill.

When you reach the end of the Wolfenstein level, before you open the door to the lastdoor enable the idclip code. Looking at the door, go into the right wall. Search around until you get to a room with another exit. Click the exit button in that room to go to a different screen with the message "You have found the super secret level. You should fly through this one." It says this because there is a Cyber Demon ahead.

When you start, display the area map and enable the iddt code. You will see a cross-shaped room at the top right corner of the map. Mark it and go to it. Once you come across a wall with a skull on a spear in front of it, press "Open" and follow the stairs. You will find a BFG9000,a Megasphere, and a pack full of ammunition.

Monsters can hear you punching air but strangely cannot hear the dull roar of an idling chainsaw.

Go to level 30, Icon Of Sin. Collect all the items, then activate the iddqd code. Go through the warp, then enable the idclip code. Go backwards until you get to the skull switch. Destroy the demon that appears with two rockets to kill it. Activate the switch. Go on the rising platform using the idclip code. Do not walk through the wall of the demon. Blast the demon's forehead (the part that makes skull boxes). This will hit the head on a stick inside. You should be able to hear a roar. The rocket box on top of the platform can be collected an infinite number of times, unless you collected the box beforehand.

If you kill a monster then an Arch-Vile brings it back, the Arch-Vile will bring it back again if it is then squished (falling ceiling effect), provided it is not mush. If this happens, then the monster will be affected by this glitch. It can walk through walls, and is relentless in pursuing you. You also cannot kill it.