raging_swan (raging_swan) wrote,

GM Advice: Principles of Megadungeon Design

Dungeons (and megadungeons) are as old as the hobby itself. Designing a megadungeon is hard, though. If you don't get the dungeon's metaphorical foundations right, you are wasting your time.


(Art: William McAusland [Outland Arts])

Over the last forty years, countless dungeons and hundreds of megadungeons have graced GM's campaigns all over the world. Designing such a locale is a gigantic undertaking. Getting its design right first time, is essential.

When designing a megadungeon keep in mind the following criteria:

Layout & Design

  • Name: The megadungeon should have a cool, flavoursome name.

  • Multiple Entrances: There should be several different ways of getting into the dungeon. While all might not be obvious (secret entrances are cool after all) most should be easy to find by all but the most blinkered explorer. Entrances set in the midpoint of the dungeon provide access to dungeon levels both above and below the entranceway.

  • The deeper you go, the more dangerous it is and the greater the rewards. This is a tradition of dungeon design. It holds true for megadungeon design as well. However, it is better restated as the further from the main entrance you go, the greater the danger and greater the rewards. Some dungeons, after all, may go up not down but could run for miles and miles at roughly the same depth.

  • Each level (or sub-level) should have its own distinctive flavour. This flavour shouldn't be unnecessarily odd just for the sake of flavour. For example, a sub-level of twisted natural passageways home to degenerate and feral derro seeking a way down to a deeper level is an example of good flavour. A level dominated by a mad alchemist who has no connection or relevance to the greater dungeon is bad flavour.

  • Sub-Levels: Smaller, self-contained areas sub-levels enable the designer to inject different kinds of flavour or monsters into the dungeon. Sub-levels may only be accessible from one normal dungeon level. Some may be secret while others may provide safe haven for explorers discovering their location.

  • There should be multiple connections between levels and sub-levels. The PCs should have freedom of choice to decide which parts of the megadungeon they explore. Access points between levels often serve as choke points. The more access points there are, the easier it is for dungeon denizens to move about and the more choices the players have. Some connections should be hidden or secret. Not all should proceed only to the next level; some may provide access to multiple levels or may miss one or two levels out (for example a connection might exist between levels 1 and 4).

  • Secret & Remarkable Connections: Not all connections between levels and sublevels should be a standard staircase. A dried up well shaft, flooded passage or chasm wall are all good examples of other connections.

  • Players should have meaningful choices: This doesn't mean the party get to choose which door to use to get to the villain's throne room. Rather, it means the layout of the complex enables the PCs to pursue multiple paths through the dungeon, exploring different areas, sub-levels and levels in the order they choose. In short, wherever possible, they should enjoy freedom of movement through the dungeon and not be forced down a set path.

  • Links to the deepest dungeon of all. The megadungeon should have one or more links to the Ebon Realm. This link provides tremendous design freedom to include strange, ancient monsters that crawl up from the lightless depths in search of prey. It essentially answers loads of tricky questions about how and why certain monsters came to be in the dungeon.

  • It should all make sense (to a certain extent). Realism is good to a certain extent, but realism for realism's sake is pointless. Worrying about the minutia of dungeon design is time spent not crafting exciting encounters and flavoursome dungeon levels and encounters. Enough information should be present for a GM to answer most basic questions about the dungeon, and no more. For example, deciding where the dungeon's denizens get their drinking water is important. Worrying about the minutia of the dungeon food chain is not.

  • Minor Elevation Shifts: Dungeon levels should rarely be flat. Minor shifts in elevation can confuse explorers. Are they on the same level or are they not?

  • Extra-Dimensional Spaces: Used sparingly, extra-dimensional spaces can provide an interesting change of pace to exploration.

  • Level Size: The dungeon levels should be of various sizes. Not all should fit on a single piece of graph paper. Some especially large levels may use a larger scale per square.

History & Minutia

  • Details, details, details. But not too many details. Empty rooms are boring. Standard corridors are boring. Dungeon dressing is an excellent cure for boring areas. Are the flagstones broken and cracked? Does dried blood splatter the wall in an otherwise empty room? Such details build on the sense of verisimilitude and give the feeling the dungeon is a live setting.

  • The megadungeon needs a decent reason for existing. A dungeon that exists because it exists is an example of lazy, lame design. The megadungeon must have or have had a reason to exist. Did an ancient race use it as their lair, or did a wizard retreat underground to continue his strange (and undoubtedly dangerous) research? Whatever the reason, it will have left its mark on the dungeon's layout, architecture and style.

  • There should be secrets to uncover. Be it secret doors, lost treasures or shocking discoveries about the dungeon itself, the complex should have secrets. The PCs should be able to uncover these as a result of good, attentive play.

  • Relevant and discoverable back story: The dungeon must have a relevant and discoverable back story. The greatest back story in the world is basically pointless if the PCs never get to interact with, discover and understand it. Knowledge of the dungeon's history shouldn't be automatic – they should have to work for it. Gaining knowledge of some or all of the complex’s history should provide insights into the dungeon (and perhaps even in-game advantages).

Denizens & Challenge

  • Wheels within wheels: The megadungeon should have an overall boss or super villain. This individual doesn't need to be in charge of everyone in the dungeon, but he should be the most powerful and influential figure therein. He will have many sub-leaders or vassals; many of these will command their own level or sub-level.

  • Away with the 15-minute adventuring day. As a player and GM, I love challenging fights. However, if every room contains a life or death struggle in which one or more PCs end up unconscious or dead the dungeon turns into an unending grind. The PCs do a room or two and then retreat to rest. That's boring game play. Instead, the dungeon design should promote long-term delving. Parties should be able to explore at least a dozen rooms before resting. Easier fights, unoccupied rooms and easily if dealt with properly battles are all excellent tools to prolong the adventuring day.

  • Wandering Monsters: Monsters don't just sit in their chambers waiting to be slaughtered. Some move about the dungeon – either because they are scavengers or because they have things to do. Having random encounters adds an extra lair of uncertainty to exploration and adds to the sense of realism of the place.


  • Settlements: One or more settlements should lie within relatively easy reach of the dungeon. This provides explorers somewhere to retreat to between forays. Here they can rest, recruit help, buy and sell magic items and so on.

So that's what I keep in mind when designing a megadungeon. Have I missed anything? Let me know in the comments below and remember you can download this – and every other advice article – for free at ragingswan.com/articles.

Tags: advice articles, gm advice, megadungeon, raging swan press

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