MAP21: Twilight Lab (Memento Mori)


Memento Mori maps 21-30

01 02 03 04 05 06 07 08 09 10
11 12 13 14 15 16 17 18 19 20
(21 - 30)
Secret maps: 31 32

This level occupies the map slot MAP21. For other maps which occupy this slot, see Category:MAP21.

MAP21: Twilight Lab is the twenty-first level of Memento Mori. It was designed by Andy Badorek and uses the music track "Mummy Rags" by Mark Klem. This level was first created by Badorek in 1995 as a standalone level, TWILAB.WAD; the Memento Mori version features several modifications for cooperative multiplayer gameplay.


Map of Twilight Lab
Letters in italics refer to marked spots on the map. Sector, thing, and linedef numbers in boldface are secrets which count toward the end-of-level tally.


Start and Red Key

Get off the silver platform and mow down all the shotgun guys, chaingunners and imps in this room. Make your way around the computer panel and enter the door ahead. take out the group of three imps and two chaingunners, then flip the switch behind them to lower a lift on the other end of this room. Ride this room down to the "central walkway". Flip a switch next to the lift to lower walls ahead, revealing the blue key in a distant room.

Follow the central walkway around to the north side, where there is a pair of doors. The sign should read "central computing/crusher/outdoor facilities". Head through the door and cut down the cannon fodder in this room. Lower the metal wall on the west to reveal a large number of shotgun guys and chaingunners - a well timed rocket or two should do the job. Don't go through the door ahead - instead, flip the switch to its left to lower the circular obstacle in the corridor.

The next area is a crusher puzzle. Several mancubi roam a red coloured floor. In front of you are several teleport pads, alternately red and white. These teleport pads don't actually teleport you, but instead control the crusher area. Since the red key is also hidden within this area, controlling the crusher correctly is essential. To clear this area with a minimum of health loss:

  • Step on the southern red pad. This raises a wall that prevents the mancubi from leaving the crusher's kill zone.
  • Step on the northern red pad. This starts the crusher.
  • Once the mancubi have been crushed and the crusher is close to the top of its cycle, step on the northern white pad to stop the crusher.

Continue through the door in the north. Follow it around and pick off the imps in this room, being careful of a nook with a couple of shotgun guys inside. Once you reach a pair of brown doors, Go through the southern one, then the one in front of you. Clear out more imps and flip the first switch panel on the west wall to lower the red key to the floor. Backtrack to the crusher (going out through the wall opened by the switch in the south restarts the crusher) and pick up the red key safely.

Blue Key

Backtrack to the central walkway. Find the red door in the east, and go through it. Open the brown wall ahead of you, and clear this room's cages of imps. On Hurt me plenty and above, there are two Hell knights on an upper platform as well. As you proceed forward, you can ignore the toxic pit if you are looking for speed or survival - just stay on dry land and follow the corridor around, killing any curious monsters from the slime area as they arrive. Once you get closer to the metal wall, it begins lowering. Ride the platform that is revealed all the way to the top (the correct alcove is in the southeast corner).

Once you reach the top, kill the shotgun guys waiting in ambush. As you continue forward, beware of a nasty trap that opens, releasing a demon in front of you and up to four demons behind you. Enter the metal door and drop down from the ledge into a small crate room with imps and demons. Take either door in the south to enter a larger crate room with more opposition. To leave this crate room, you need to:

  • Find the crates forming stairs in the south of the levels;
  • Climb up them to a grey platform with shotgun guys;
  • Drop down to the east;
  • Continue east, stepping over a pair of small crates. This lowers a pillar ahead with a chaingunner. Kill it and get on the pillar.
  • Ride the pillar up, then jump to the brown crate with a health bonus.
  • Face north, then run to the grey platform.
  • Standing at the southeast corner of this platform, face west, blow up a barrel ahead (if it is still there), then run all the way west to the grey platform with a tiny crate on it (be careful not to overshoot!)
  • Face north. Use the tiny crate to climb up, then drop down into a concealed area with a door.

Exit through the door, then drop down the ledges to come to another door. Kill the mass of former humans here, then find the only non-blue-locked door in the northwest. Use the sides of the pedestal the blue key is on to lower it to the ground for collection.

Yellow Key

From the blue key room, drop into the water through the windows. Find the metal strip on the wall and use it to lower a lift to a high ledge. From this ledge, run back onto the central walkway.

Your next destination is the blue door in the west of the central walkway. Go through it to a stone-walled room with a slime pool. There are some up to four cacodemons (six on co-op) to handle in this room. Walk around the slime pit on the stone walkway and stairs will rise up in front of you. Go up the stairs to an alcove with a switch. Flip the switch and the wall will lower, revealing a new room (on Ultra-Violence, there is a revenant in here). Directly facing the switch in the west wall, walk east towards it to lower a wall in this room and reveal an alcove opposite with pain elementals and lost souls. Flip the switch to raise a bridge to the alcove. Cross the bridge and flip the switch in this alcove to acquire the yellow key.


From the bridge, drop down to the south and re-enter the blue door. This time, go through the door in the southwest corner. Follow the blue lights on the floor south to a pair of doors, then east. Open the first of three small doors on your right.

This room has a U-shaped walkway, some cacodemons, and on Ultra-Violence and above, a pain elemental. Once you've taken out the monsters, drop into the water and press use on the yellow bar in the water. This unlocks the exit room. Lower the walkway around you to get back up, then exit the room.

Back in the hallway, notice that the centre door of the three small doors is now open. Step into the hole in the floor in this room to exit the level.

Other Points of Interest[edit]

Optional Area 1: Computer Maze and Central Computing

From the pair of doors in the north of the central walkway, enter the room ahead and walk into of the dead-ends formed by computer panels on the east side. Lifts will lower, taking you into a red-floored maze filled with former humans, lost souls and demons. At the far east of the maze, one corridor contains a drop trap, lowering the floor into an ambush with two shotgun guys. From there, lower either metal panel in the corridor to access the Central Computing room. The ledge has some shotgun guys. Try not to fall off the ledge unless you want 100% kills - to get back up, you will have to lower the ledge, which in turn releases numerous cacodemons and pain elementals.

To exit this area, leave by the metal panel in the southwest. In this next corridor, you can lower the western metal panel to be lifted back into the southeast corner of the red-floored maze, or lower the southern panel to be taken to a red door, which leads you to the area just behind the red door in the central walkway.

Optional Area 2: Outdoor Facilities

This area can be accessed either by going through the small door in the northwest of the central walkway and ascending the staircase (run across the final gap), or by opening the metal door just before the crusher area and taking the lift up. Make your way to the platform in the west with a baron of Hell or two, and step on the platform to lower a wall behind. This new passageway leads to a stone-walled indoor room with an arachnotron (two on Hurt me plenty and above). Flip the switch on the west wall to lower part of the east wall, then run through that gap to acquire the previously unobtainable soulsphere.



  1. Upon going down the elevator from the start area, head near the first red door. In the corner opposite of this door is a section of wall covered with a spray-painted X. Open this wall to reveal a hidden room and then walk across the north of the rock pit to reveal a secret compartment (sector 32) containing three lost souls, a plasma gun(, a bulk cell on easy and medium skill levels) and two energy cells.
  2. Enter the first red door mentioned in secret #1 and then the northernmost door. Lower the dark metal lift and ride it up to encounter four sergeants and a chaingunner. Open the dark metal wall in the east to enter a room called Central Computing as indicated on the signpost nearby the first red door. This is a room with a walkway (and some sergeants) along the edges; drop into the pit and press on the inner sides of the walkway to lower it like an elevator. This will reveal an ambush with cacodemons (and pain elementals on hard skills) and two holes in the northeastern corner of the room. Enter either one of these to find a secret alcove (sector 125) with two lost souls, two sergeants, (skill dependent) none/two/four chaingunners and a berserk pack.
    The Central Computing room can also be accessed by exiting secret #1 into the hallway, entering either door in the northern wall, approaching either health bonus in the east to ride up a lift, reaching the east of the red floor maze to ride down a lift and proceeding through the passage there.
  3. Upon entering the Toxin Experiment area (through the first red door, then the door right east of it), pass the hallway, ascend either stairway and flip the switch to lower the imps' alcoves in the north of the hallway, revealing a hidden alcove (sector 398) between those with three rockets and a stimpack.
  4. In the Containment Area (crate storage) is a computer console (sector 225) upon which three health bonuses and two armor bonuses rest. Head over to the south of the room and ascend the stairs building crates to encounter some sergeants and to reach the room's southeastern part. Drop down on the floor to the east and follow the passage to kill a demon. Approach him, walking over the small crates so a pillar will lower like an elevator, revealing a chaingunner. Take this elevator up, jump onto the brown crates (with a health bonus) to the west, and then jump over onto the gray crates to the north (with two barrels, (a chaingunner on medium and hard,) a sergeant and an imp). (Return to this point to access non-official secret #4.) From there, jump west across the gaps to the brown crates (sergeant and barrel) in that direction, and then the gray crates (imp). Jump across the next gap to the gray crate (health bonus) and then navigate the gray crates over to the northwest. Head over to the eastern edge of the last crate stack, and then jump on top of the console to register the secret.
  5. In the gray stone room with the toxic pool (behind the blue door west of the elevator you rode down from the start area), there is one patch of wall in the south that is green. Open this wall and the one after it to access the brown sludge pit in the southern room. Behind the mechanical structure is a secret alcove (sector 322) containing a bulk cell and a megasphere. To exit the pit, take the elevator in the west of the alcove, and then lower the railing to the west.


  1. In the starting area, walk onto the eastern blue pad from the northern side. It will lower you into a concealed room with two lost souls, a megaarmor and two health bonuses.
  2. From the switch mentioned in official secret #3, proceed to the east, pass the door to the south and follow the walkway. Before descending the stairs, open the differently textured part of the northern wall to find a compartment containing a chainsaw.
  3. After exiting non-official secret #2 and descending the stairs to the west, push the metal wall to your right to lower a lift leading to the imps' alcoves in the south of official secret #3's hallway where you find a rocket and three health bonuses.
  4. From the point (the first gray crates) mentioned in official secret #4, drop down on the brown crates to the north. Follow the walkway built by these around the corner to the right, jumping over a gap to find a computer map.


Demo files[edit]

Areas / screenshots[edit]


Routes and tricks[edit]

Current Compet-n records[edit]

The Compet-n records for the map are:

Run Time Player Date File Notes
UV speed 03:26 Oyvind Stenhaug 2003-06-04
NM speed 02:57 Artem Safronov (SAV88) 2007-02-14
UV max 11:48 Chris Ratcliff (Ryback) 2002-03-24
UV -fast 13:16 Revved 2011-04-25
UV -respawn 09:29 Revved 2011-06-05
UV Tyson
UV pacifist

The data was last verified in its entirety on July 4, 2020.

Current DSDA records[edit]

The records for the map at the Doom Speed Demo Archive are:

Run Time Player Date File Notes
UV speed 2:52.29 Andrea Rovenski (Cyberdemon531) 2015-01-04
NM speed 2:57.00 Artem Safronov (SAV88) 2007-02-14
UV max 8:44.17 Andrea Rovenski (Cyberdemon531) 2022-10-09
NM 100S
UV -fast 13:16.03 Revved 2011-04-25
UV -respawn 7:41.91 Andrea Rovenski (Cyberdemon531) 2015-01-08
UV Tyson 47:10.49 Andrea Rovenski (Cyberdemon531) 2015-12-01
UV pacifist
NoMo 1:35.69 MD922 2015-01-05

The data was last verified in its entirety on October 24, 2022.


Player spawns[edit]

This level contains six spawn points:

  1. facing south. (thing 35)
  2. facing east. (thing 546)
  3. facing north. (thing 547)
  4. facing east. (thing 548)
  5. facing west. (thing 771)
  6. facing north. (thing 772)


Map data[edit]

Things 773
Vertices 2587*
Linedefs 2813
Sidedefs 3788
Sectors 444
* The vertex count without the effect of node building is 2294.


This level contains the following numbers of things per skill level:

Technical information[edit]

Inspiration and development[edit]

The map received numerous changes between the original December 1995 release and the final version, however all of these changes were very small and largely inconsequential. Here's the list of changes made in the final version:

  • A few of the rooms were retextured.
  • In the area leading to the blue key a wall switch was added that lowers the floor to the nearby crate area. Also, one of the tall blue torches was replaced with a lamp.
  • Map geometry was tweaked slightly in a couple of places.
  • A couple of deathmatch starts were added, along with several multiplayer-only sets of green armor.
  • An energy cell pack was added to the baron room in the south.
  • A few miscellaneous items as well as barrels were added to some places on the map. Certain items and monsters were slightly moved.


See also[edit]


External links[edit]