MAP18: Optional Bases Opposed (BTSX-E2)


Back to Saturn X E2 maps 17-23

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(17 - 23)
24 25 26 27
Secret map: 31

This level occupies the map slot MAP18. For other maps which occupy this slot, see Category:MAP18.

MAP18: Optional Bases Opposed is the eighteenth map of the second episode of Back to Saturn X. It was designed by Paul DeBruyne (skillsaw) and uses the music track "Birdsong," composed by Stuart Rynn (stewboy). In the official add-on version, this level's name is Strange Fates for Theodore.

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Map of Optional Bases Opposed
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.


Other points of interest[edit]



  1. Southwest from the start, near a pool of slime with two dead marines and the chainsaw, there is a ring-shaped structure where a soulsphere is visible in the center (sector 562) through a small window. Press on the nearby green torch to lower a wall leading to it.
  2. At the north-eastearn part of the map is an elevated section of the level, where a soulsphere is visible on a pedestal. Near the stairs to that section is a square shutter. Press on it to open a small compartment (sector 96) containing a berserk pack.
  3. Ascend the stairs from secret #2 to find the soulsphere with a computer nearby. Press on the computer screen to lower the pedestal (sector 140), allowing access to the soulsphere.
  4. On the north-central part of the map, a button can be pressed to lower a rocket launcher, and which also lowers some walls containing monsters. On one of the monster closets that opens next to the rocket launcher, there is a hidden switch with the image of a crucifix. Shoot that switch to reveal a teleporter on another of the monster closets nearby, allowing you to telefrag two arch-viles in the beginning area and eventually access a fenced off courtyard (sector 787) guarded by two arch-viles (on Ultra-Violence and higher), containing a soul sphere, shotgun shells and armor bonuses.
  5. On the easternmost part of the map, shortly before finishing the path that ultimately leads to the red key, there is a desert-like area surrounded by blue torches where you are ambushed by teleporting monsters. You can use three small pilars on that area to climb to a small section containing a tiny hole. Falling down that hole leads to a small underground secret area (sector 509) containing a soulsphere, two boxes of rockets, and a medikit.


On the western part of the map, at the start of the route leading to the blue key, there is a section with a zig-zag shaped path which ultimately lowers to reveal two arch-viles and a button unlocking a plasma gun and allowing to proceed further down the path. That same button also opens the bars to another section to the west which requires either the red or the yellow key and contains a BFG9000.


Demo files[edit]

Areas / screenshots[edit]


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.


Player spawns[edit]

This level contains seven spawn points:

  1. facing north-east. (thing 35)
  2. facing north-east. (thing 570)
  3. facing west. (thing 571)
  4. facing south. (thing 572)
  5. facing north. (thing 573)
  6. facing west. (thing 574)
  7. facing east. (thing 575)


Map data[edit]

Things 930
Vertices 5893*
Linedefs 5985
Sidedefs 8735
Sectors 992
* The vertex count without the effect of node building is 4901.


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

Technical information[edit]

Inspiration and development[edit]


See also[edit]


External links[edit]