We Have Always Lived in the Megadungeon

 I have on occasion riffed settings which were small or at least smaller than the typical D&Dish setting. This goes against the grain of published settings which tend to want to give you big, as in a world big, and perhaps classic play which starts circumscribed, but is about expanding the frontier.

There is one archetypal D&Dish experience that doesn't quite work this way and that's the megadungeon. Certainly exploring the megadungeon means opening up more area, but the scale is so much smaller generally than the hexcrawl. Distance is not a primary factor.

It strikes me that the dungeoncrawl could easily combined with the player's living space. Megadungeons under towns are pretty common, but then the town becomes a place of relative safety and refuge that may or may not enter into actual play as anything more than "base camp." What if the megadungeon space and the living space bled into each other? Like say the PCs lived in a place like Gormenghast or Xuchotl from "Red Nails," or the starship Warden, and the exploration was progressively moving into rooms, levels, sections or whatever that were unknown? (You could perhaps include small settings with actually dungeons/underground spaces in this. See MacDonald's The Princess and the Goblins.)

This could be combined quite easily with the mystery sandbox. Indeed, the incremental accumulation of vast wealth is probably a bad goal for a smaller setting of this sort. Not that money might not be a motivator, but the real big payoffs should only come at the end.

Obviously, this sort of setting would differ from the standard D&D approach even without the downplaying of vast wealth. Parties would likely be less eclectic. The length of the campaign is probably somewhat limited without a change in approach unless the structure they reside in is really weird, but I think it would make for interesting low level play.