hostile architecture

    making dungeons really work against the players, down to the bones. this isn't about traps that do things to the players. alone, these things shouldn't pose a challenge (i.e. without any pressure, this wouldn't require a roll), which is why you throw enemies at the players while they're navigating it.

the classics:

• rickety rope bridge over chasm
• shooty enemies pop up when you're halfway across. i'm not a huge fan of "uh oh that monster is sawing through the ropes!"
• maybe even just a chasm, no bridge. something tasty is on the other side. the players can figure it out.
• various traps to divide the players:
• from matt colville: chute trap sends a few of them sliding away from the party. they are now Somewhere Else. the party must reunite. send enemies at one group.
• also from matt colville: portcullis slams down and divides the party. send enemies at both groups. portcullis because players can see eachother and reach through the bars.
  
• "press both pressure plates to activate the door." send enemies at both groups.
•  if you can't decide which group of players to send monsters at, the answer is always the squishier one.
• tall, tall ceiling, can't see what's up there!
• i like catwalks. enemies can harass the party (especially if they fly) but the players can get up there too.
  

    then there's stuff for locations that weren't quite built for people to use. the pyramids are an example. no one is going to be using the space after its built, so the architecture can get weird without breaking verisimilitude. "what do you mean how were people supposed to get around in this place? they weren't." strange alien spaces that reject humanity.

• verticality. forget slopes. forget stairs. any time you would have a slope or a staircase, have the higher and lower passages connect with a vertical shaft. i'll draw a picture cuz it's hard to explain with words.
• doing it for every slope might be too much!
• don't forget to throw enemies at the party while they're trying to get up or down. have them knock down the players' ladder, or cut their rope.
• can go even further. vertical shafts. nothing to climb. big pit. something nice at the bottom.
• or maybe don't forget slopes. steep smooth slopes are fun. slide into something dangerous?

like this.

• small passages. you gotta crawl through it. can range from hands and knees to on your stomach.
• some PCs might not even fit! there's gotta be a different path though.
• don't forget to throw small crawly enemies at the party while they're trying to go through.
• for extra fun, make the heavily armored character have to take off their armor to fit.
  
• thin walkways. no guardrails of course.
• shooty enemies. or ones that can drag/push the PCs.
• protrusions from the walls or ceiling. chest height, make weapons harder to use.
• probably pair with something that doesn't attack using arms.
• not from the floor, that's just called cover.

    weirder stuff. problem with these is that it feels mostly like "i, the dm, put these here as a challenge for you, the players." and not "yeah someone built this." maybe you can execute these in a way that works better.

• playgrounds are great for physicality. seesaws, jungle gyms. great for less serious adventures just gotta spice em up and give them that dungeon flavor.
• spikes on the ground. not a problem to walk through, the spikes are short and widely spaced enough. combine with enemies who are trying to knock you over, and don't suffer from being knocked over themselves, like skeletons.
• strange materials, pitch black stone, invisible walls, ice, gel, etc. haven't figured out a great way to use these yet, but there's potential.