A while back folks at EN World were posting about using 4E to run a megadungeon sandbox, and I thought it’d be appropriate to revise and repost my comments there for a couple of reasons. First is the Mule’s mandate to carry loads of treasure and supplies wherever adventurers go, be it old school or new. Second is our collective experience with Paul Jaquays’ Caverns of Thracia, which Grognardia recently called as close to a published megadungeon as anyone’s ever gotten. Finally, having been paid to write some first- and third-party stuff for the Fourth Edition of Dungeons & Dragons emboldens me to gas on about it for free.
Here are what I see as the elements of the old-school system (rules, assumptions, etc.) that are essential to the play style that thrives in and around a megadungeon:
– Experience points are awarded primarily for finding treasure and surviving long enough to bring it out of the dungeon. The XP you get from killing something is more or less trivial compared to what you get from looting its lair.
– Wandering monsters are a constant hazard with a fixed and more-or-less known to the players rate of random occurence, so that the decision to search every cranny is balanced against the risk of an unplanned encounter of unknown lethality. There’s little guarantee that each fight will be carefully balanced to be overcome by the adventuring party once they expend some fraction of their resources. Even on the first dungeon level, you might encounter something that’s way too powerful for you to fight head-on.
– Magic items are mysterious (there’s no easy recourse to the identify spell or an arcana skill check) and as likely to be a bane as a boon (e.g. cursed items, intelligent swords with conflicting agendas, etc.).
The reason that these are important to the megadungeon is that the dungeon is supposed to be an intrinsically dangerous environment, at best a constant impersonal hazard and at worst an enemy in itself. Mapping is essential because nothing is worse than losing your way back to the surface. Your initial focus isn’t clearing out every room for experience like in a CRPG (although that may happen over time); the megadungeon should be about going in, exploring, and making strategic choices (do we open the door with the spooky noises, or push on further; at what point will the depletion of our resources, from HP to torches, force us to turn back given that we’re likely to face a number of wandering monsters just trying to return to safety), balanced against the certain knowledge that you’re surrounded by things that will kill you dead if you’re not both careful and lucky.
If killing monsters is the main source of experience as per the 4E rules-as-written, there’s going to be a strong incentive for the players to treat each encounter as the next step towards leveling up, rather than a potentially much-more-lethal-than-expected hazard that’s better negotiated using brains rather than brawn. To run a 4E megadungeon I’d eliminate or sharply reduce the XP award from monsters, replacing it with XP from treasure awarded (or quests if you want to be a little less old-school).
This ties into the wandering monster issue – if the PCs are noisily bashing down doors, you want the resultant increased risk of a wandering monster to be a punishment, not a gift of XP. This is especially true because the random factor might make the gift a trivial gimme – fire beetles! – or a Trojan horse – trolls! – so again it’s important for the players not to have a system-reinforced expectation that monsters are there to be killed. The other 4E problem with wandering monsters is that combat takes so much longer than in the old-school. You want the fire beetle encounter to be a punishment for foolhardy play in that it dings the PCs by a few hit points, not in that it forces the players to wade through an hour of dull (because ultimately unchallenging) melee. Mike Mearls’s Keep on the Gaming Lands has a post describing a system for wandering monsters in 4E that’s insightful (even if my experience suggests that even an encounter a few levels lower will still eat up more time than I think dealing with a wandering monster ought to), while his skill challenge for sneaking through the steading of the hill giant chieftain promises to do some of the things I’d want wandering monsters to do (impede the PC’s ability to move around the dungeon unimpeded).
Finally, magic items are a problem because one virtue of the megadungeon is that it’s entirely up to the players which direction to head, making it hard for the DM to place the items magic items 4E expects the PCs to find at level-appropriate moments. And the expectations that creates in players is counter to the old-school feel; a cursed item should be like “well, I invaded someone’s house and caught athlete’s foot from the shoes I stole, I guess that’s what I deserve” instead of “these shoes I got for my birthday have a fungus?!?” What I’d do is to abstract out magic item enhancement bonuses, similar to how it’s done for NPCs. When you hit second level, choose one item (armor, weapon, implement, etc) to receive a +1 enchantment bonus, which is conceptualized as just another benefit of increased experience; it’s that you’re better with your sword, not that your sword started to glow. At third through fifth levels, choose another item; at sixth level, one item gets bumped to +2; and so on. The strange and custom-created items you find in the dungeon will contribute the other aspects of 4E items (e.g. item powers), and since players are reassured that the PCs will keep up with the expectations built into the system, they ought to be a lot more open to items that have unknowable / undesirable / unreliable “special” effects.