MAP26: Beneath a Festering Moon (BTSX-E2)


Back to Saturn X E2 maps 24-26 & 31

01 02 03 04 05
06 07 08 09 10 11
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(24 - 26, 31)

This level occupies the map slot MAP26. For other maps which occupy this slot, see Category:MAP26.

MAP26: Beneath a Festering Moon is the twenty-sixth and final proper level of the second episode of Back to Saturn X. It was designed by Xaser, who also composed the music track, "Angry Science." In the official add-on version, this level's name is Angry Science, taken from its track title.

Beneath a Festering Moon was featured in Doomworld's Top 100 Most Memorable Maps, placing 19th.


Map of Beneath a Festering Moon
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.


Go up the steps to a shotgun then open the red door and go round the corner to a teleporter. Step into the teleporter and flip the switch in front of you, which will slowly raise bridges around the base of the tower, then kill some cacodemons that teleport in while you wait for the bridges to reach the correct heights. Follow the path round to a Hell knight then turn left to drop down to a second bridge which leads to a door, which has opened to reveal an armor guarded by a chaingunner. Go through and enter the right-hand room to collect a chaingun, then duck under the girders by hugging the central column so you can reach the north door; pass through it and go forward to a berserk pack, which will release an arch-vile into the room behind you, then go back there and head through the now-reachable west door to kill a couple of demons and chaingunners. Go through the blue door then open a second door on your right to confront two arch-viles, who are guarding a partial invisibility and a switch located between the flesh tanks.

Flip the switch then go back to the previous room to see that steps have risen leading up to a pool of purple liquid, which is damaging. Climb up to the vent in the south-east corner and follow it to a button, which will open the door to the tower, then head back across the bridge and go inside to find a super shotgun and a megaarmor. Turn right and head down the steps to a booth, go inside it and kill or avoid an arch-vile that lowers in the center of the room, then pull the switch to raise a set of steps on your right that lead up to a door; this will cause one or two more arch-viles to teleport in. Go through the door and kill some spectres and chaingunners waiting in the next room, then go through another door on the east side and walk through a narrow passage to a room containing a rocket launcher. Drop down the hole in the center of the room to go to the second level (the north-east section of the map).

Step off the pad, noting the chaingunners and other monsters behind you, then turn right and drop down the steps to enter the south room; the column in the center of the room contains another hole leading down to the third level (the south-west section of the map). Kill the imps, cacodemon and pain elemental waiting here then go up to the north-east room and enter the teleporter in the center to go back up to the second level; you will be inside the cage that held the chaingunners. Press the "LOCK" panel to open the large door just ahead, pass through it and cross the bridge to enter a brick chamber with a couple of knights. Go down the steps in the north-east corner to enter a hall, then go behind the altar at the far end to find a hidden button that will lower it so you can collect the plasma gun. Stepping off the altar will cause the hall to fill with blood, bringing in four revenants, an arachnotron and one or two pain elementals.

Leave the hall through the opening in the south-west corner and step into a cavern with a shotgun, then follow the path north-east down into a chamber with boxes that is overlooked by chaingunners and a knight. Step past the purple light in the south-east corner to find some narrow steps, then follow this path north and west past imps and chaingunners until you reach a rocket launcher. Go down the steps to find yourself in a clearing with a circular "vortex machine", where multiple arch-viles will appear and start resurrecting the monster corpses in this area. Kill them along with some cacodemons and revenants that teleport in, approach the machine to raise a lift leading up to the vortex, then step through to end the level.

Other points of interest[edit]


  1. On the third level of the tower, which contains three similar and connected rooms with coolant waterfalls that create a pool with a column in the centre, the waterfall in the north-east room can be passed through and contains a teleporter to a large flesh-ridden zone (sector 1260) with a backpack, a megaarmor, a supercharge, a lot of ammo, and a big ambush by several arachnotrons and spiderdemons with revenant snipers at the edges of the coolant lake. The teleporter in the center takes you back to the regular map.
  2. Inside secret #1, a small passage (sector 508) can be found in the southern-most part of the arena, behind the fountain of damaging coolant, containing an invulnerability.
  3. Right after the entrance of the building decorated with red runes all over the walls, veer to the left and you'll spot a damaged wall with some broken bricks on the floor. The bricks are climbable, so hop on then and into the hole in the wall (sector 905) to find an armor.
  4. In the cavernous section leading to the vortex machine that contains the end of the level, the computer area map can be easily spotted on a ledge. Immediately before is a very big and deep hole with highly damaging lava at the bottom. There is a small entrance along this hole you can drop to (hint: the floor of the entrance can be seen without dropping down with proper positioning and high gamma correction levels) to access a secret lift (sector 746) that takes you to the map.
  5. In the final area of the level past the vortex machine, an invulnerability can be seen in a fenced off balcony, but the door to access it is locked. Press on the tan wall directly opposite the locked door to lower it and access a series of narrow passages, at the end of which there is a sharp bend with a switch on a pillar and a supercharge further ahead. Pressing the switch will unlock the door to the balcony (sector 887) with the invulnerability. Collecting it will teleport you directly to the area of the final fight in front of the vortex machine.


Demo files[edit]

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Routes and tricks[edit]

Current records[edit]

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

Run Time Player Date File Notes
UV speed
NM speed
UV max
NM 100S
UV -fast
UV -respawn
UV Tyson
UV pacifist

The (absence of) data was last verified in its entirety on February 21, 2022.


Map data[edit]

Things 938
Vertices 7744*
Linedefs 8569
Sidedefs 13100
Sectors 1409
* The vertex count without the effect of node building is 6470.


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

Technical information[edit]

Inspiration and development[edit]


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