Looking back at some of my unfinished #doom maps... I think I'm done with mapping for Doom engine games anymore, though someday I hope to at least finish this one. The idea is that "hellfire" hurts the player. This wasn't done with sector effects, but with actual ambient light values and some K8-specific ACS code reading those values. I was going to make some player movement puzzles based around this.
This was going to be an installment in my Eschatology series.
https://www.youtube.com/watch?v=mWmHHBqgKrg
https://www.youtube.com/watch?v=3_XE6YDebNM