MAP20: Bony Encounter (1 Monster)


1 Monster maps
First episode

01 02 03 04 05 06

Second episode

07 08 09 10 11

Third episode
Final episode & Secret

21 22 23 24 31

This level occupies the map slot MAP20. For other maps which occupy this slot, see Category:MAP20.

MAP20: Bony Encounter is the twentieth map of 1 Monster. It was designed by Kristian Aro.

Like all maps in the megawad, the map features only one type of monster, in this case the revenant. It is set in a brick scenery somewhat reminiscent of MAP14: The Inmost Dens.


Map of Bony Encounter
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.


Grab the items, including the super shotgun, and press the switch that will rise to the west. Revenants will teleport in, so quickly run to the southern door which has now opened. Head forward, along the ledge, and into the next room. Go up the stairs and keep going forward; at the end of the outdoor area, press the large skull switch that will appear. Go back into the previous room. Bars have now risen; press the lion switch at the end. This opens a nearby door. Head in - a wall will rise to the north, revealing a rocket launcher - and down the stairs, then go outside. Climb the stairs and open the door to the south. Press the lion switch.

Go back to the beginning of the level. The northern door is now open. Head through and grab the red key at the end of the area. Head again to the outside area where you climbed the stairs previously, and open the red key door to the north. Head in, grab the radiation shielding suit, and keep going forward until you come to a room with two blue skull symbols. Go up the stairs and press the switch. Head back to the river of acid; a door has opened in the southern wall, behind which is the blue key.

You now have two possible routes. You can go back down the river into the room with the blue key door to the north. Or you can use the nearby teleporter to head back to the beginning area, where there is a blue key door; head in and keep going forward, and you'll find some goodies on your way. Either way, you'll end up in the same room, with two burning red torches and four passages on four walls. Both the north and the west passage will lead you to the same large lift. Wait for it to rise and press the switch to the west. It will reveal a switch in the south-east corner; this one reveals another switch in the opposite corner, and so on. Once four switches in four corners are pressed, you can get the yellow key. Head down a passage to the north and press the switch there to lower the lift and let you leave. Go back to the room with two torches and leave through the blue door here. The yellow door is next to you. Open it and head to the exit.


  1. In the outdoor area with the red skull key door, head up the stairs and check near the large wooden door to the south. Part of a wall behind a tree is more cracked than the surrounding walls. Open it, and you will find a secret passage with some health bonuses, and a lion switch at the end. Press it to open another secret door downstairs, near the entrance door to this area. Walking inside this second passage triggers the secret. (sector 122) Within is a megasphere (singleplayer and cooperative) or a supercharge (deathmatch), as well as a energy cell pack. Picking these up will open a niche in the passage, containing a revenant and a box of shells.
  2. In the area with the red key, drop off the bridge, to the east. In the south-east area of the pool you will find seven armor bonuses, a supercharge (singleplayer and cooperative) or a rocket launcher (deathmatch), four (Easy) or two (Medium) rockets, and one (Medium) or two (Hard) boxes of rockets. Stepping on the platform with the ammunition triggers the secret. (sector 306) To escape the damaging floor, you will need to walk around the entire bridge and use the teleporter in the south-western area.
  3. On the back of the postument with the red skull key is a switch which summons an invulnerability sphere (singleplayer and cooperative) or a megasphere (deathmatch) when pressed. The secret is triggered when you approach the switch very closely, stepping on the southern part of the red section of the floor. (sector 357)
  4. When you approach the red skull key, a large niche opens in the lower part of the outdoor area with the red key door. Apart from several items and enemies, the niche contains a switch which opens another secret niche behind the entrance door to this area, containing a megaarmor and three energy cells. The second niche counts as the secret. (sector 465)
  5. In the passage between the underground green acid river and the room with two keyed doors, a part of the wall is more cracked than its surroundings. It is a secret door, behind which is a box of shells, a box of bullets, and a backpack. (sector 619)
  6. In the level's beginning area, there is a blue skull door. When you enter and go down the corridor, a niche in the wall ahead of you will open; it only opens once, so you must hurry to get inside before it closes again for good. Within is a BFG9000, as well as a revenant. (sector 368)
  7. In the room with two red torches (before the lift leading to the yellow skull key) one of the walls on the western part of the stairway has a different texture than the rest. Open the wall to find a switch that opens a secret niche downstairs. It contains a stimpack and armor. (sector 716)

Areas / screenshots[edit]


Current records[edit]

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

Run Time Player Date File Notes
UV speed 4:38.37 Ilya Lazarev (joe-ilya) 2017-09-26
NM speed
UV max 7:24.29 vdgg 2015-03-23 Plays back with 1monster_bugfix.wad
NM 100S
UV -fast
UV -respawn
UV Tyson
UV pacifist
NoMo 1:55.83 Doomdaniel95 2013-12-01

The data was last verified in its entirety on November 29, 2021.


Player spawns[edit]

This level contains seven spawn points:

  1. facing south. (thing 402)
  2. facing north. (thing 403)
  3. facing west. (thing 404)
  4. facing west. (thing 410)
  5. facing south-east. (thing 411)
  6. facing south-east. (thing 413)
  7. facing west. (thing 421)


Map data[edit]

Things 466
Vertices 7617*
Linedefs 7437
Sidedefs 12273
Sectors 753
* The vertex count without the effect of node building is 6020.


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

Inspiration and development[edit]

In the map's first versions, the beginning of the level was much harder, as it had more than one revenant hiding behind doors in the first area.

External links[edit]