Unsure if this should go in Mods & Resources, or Editing Tutorials, but anyhow...
Here's an example map/template to end the level when everything has been killed. Requires complevel 9 (or higher) and UMAPINFO, relies on some Dehacked edits.
https://user.fm/files/v2-6268e70b5dcf9f2fdd5a52d190d26bd1/umapend.zip
Tested with dsda-doom 0.27.4, Woof 12.0.0.r85 (git), Eternity 4.03.00.pre.r1227 (git), GZDoom 4.11, PrBoom+UM 2.6.66
There still might be a bu