A while ago, there was a reddit post seeking advice for improvising fantasy dungeons for a D&D or OSR-style game.
While I usually come in to each session with about an hour of prep, some of my favorite memories at the table are from RPG dungeons and adventures that I improvised with little-to-no prep time. It can be intensely rewarding to run improvised adventures, but self-doubt, faltering when unsure of what to do, and anxiety can lead to very unfun experiences at the table. After years of GMing, I have developed strategies for creating a simple, fun adventure when I don’t have time to prep like I usually do. Following these methods allow me to quickly come up with some ideas which I can riff off as we go through the adventure.
Steps for running a dungeon on five minutes prep:
- Pull up blank dungeon map from Dyson Logos or another source. Print it if you want.
- Pick one or two interesting themes, such as the ones below:
- insect hive
- undead praying at altars to old gods
- two rival factions
- large marble statues everywhere
- Pick an important monster or type of monster that fits the theme. Give it a unique trait. This monster will play a central role in the dungeon.
- Example: If we had the undead praying at altars theme, I would quickly find the stats of a moderately challenging undead. Then for its unique trait, I might decide that these undead carry large stone crosses on their backs, and use them as weapons.
- Pick a room on the map that looks important and place there the monster(s) that I chose in step 3.
- Usually, this is enough to start the game. At the table, describe the entrance to the dungeon based on the theme.
- As they start to explore the dungeon, present the players with some vague clues involving the theme, important monster, or anything else. Based on what the players interpret about the dungeon and how they react, improvise monsters and encounters leading to the important room chosen earlier.
- When in doubt, stop for a second, look at the map, and think back to the theme. Describe a single sensory input (feel, temperature, smell, etc) for the situation, then use vague foreshadowing of something nearby, which gives yourself time to figure out what is actually nearby.
- Then, keep going, filling rooms as you go and liberally steal ideas from the players – if they say “Oh, I think we should try kneeling with the wights to pray at this altar, maybe then they will let us through the locked door!”, then you as the GM should run with that idea and make it happen, even if it wasn’t something you had originally intended.
Running a dungeon with half an hour of prep:
For a 30 minute prep dungeon, I do a similar process but I steal liberally from other sources.
- Pull relevant fantasy novels or RPG books off my shelves, flip through randomly and stop when you see something cool, jot it down on the map.
- Come up with lore as you go, leave lots of room for improvisation. Plan obstacles, not plots.
- Come up with one or two NPCs and what makes them unique, then place them on the map.
- Run the session loose, liberally deviate from what was planned, and feel free to rearrange things as you go.
- Keep the action moving, and make sure the characters always have something to interact with or a problem to overcome.
- Don’t take yourself too seriously. Everybody is here to have fun, try to have some yourself.