A discussion by email with Douglas Pearson led me to this. I mentioned that I'd apply some of what I learned by doing my megadungeon differently, if I could do it again. So what would I do?
If I could do it again . . . let's break this up into "definitely do differently" and "might do differently."
Definitely Do Differently
More Notes On The Maps
I've done this subsequently, but not initially. My maps were direct copies of the style I used when I was mapping dungeons back in elementary school. As such, they depended heavily on map keys. It's better to make the maps visually communicative than visually impressive. It's a tool, not a piece of art, even if some people's maps are art as well (cough, cough, Matt Jackson, Dyson Logos).
Easier to Explain Rooms
Honestly, the crazy room shapes and double-L rooms and 40x50 rooms with a 10x10 block covered up and an attached triangle-shaped room were fun to draw. But they take freaking forever to explain to people. My vocabulary has not been up to the task. Next time, none of that crap. A bunch of easy to explain room shapes 90% of the time would be better. Sure, have some weird ones. But make them exceptional and interesting (even if just visually). But the easier they are to explain to mapping players, the better. The fun is exploration and fighting stuff and taking their treasures, not trying to explain how that room is shaped because you used a 25 degree angle wall to slightly open out to the left before it jughandles around into an L-shaped connecting corridor. Gah.
Mark How Doors Open
I remember how they open, which direction, etc. from repeated play and notes. But damn, I wish I'd just used proper marks for doors. I've marked the newer maps this way.
I think both I and my players would be happier if I had more ways to easily change levels in my megadungeon. I mentioned this before. I have some places with very easy multi-level access. But allowing easier transit would make for, in my opinion, a dungeon experience that provides more choices and yet easier choices for the PCs. They'd be confronted with "go back, stay here, or go further?" much more often. It would also make it much more difficult to fully clear your six, making for more risk at the some time as giving more potential reward (and making it possible to vary your path on the way back to avoid ambushes, too.)
More level changes possible right away, that's what I would do differently.
Not A Mountain
A mountain seemed like a good idea. It isn't, because all too often I've had to think "Well, wouldn't this level extend off the side of the mountain?" Yes, and I've had to re-orient too often. A low hill with extensive tunnels under it would have been fine, because I wouldn't have to consider height and all of that stuff.
Easier Access Into The Dungeon.
I love my megadungeon. I especially like, conceptually, the idea of the fortified entrance. I haven't seen one that quite did what I made. But I was tempted when I wrote it to make a big central room with lots of staircases and choices. Hallways in all sorts of directions, a big damn staircase down connecting a few levels together immediately, and plenty of choices. I didn't for a few reasons.
One is that I wrote my megadungeon for immediate play. I was still writing when the players arrived, and still writing as they explored it (and I'm still writing now). So "you have free access to all of 4 levels" means "I have to have 4 levels completely stocked up, along with all places you can get from them, right now." That wasn't possible. So I had to make at least the upper levels restrictive.
I also had a story - the dungeon was built as an underground fortress, which was connected (either deliberately or not . . . ) with deeper levels. It was stormed and looted. Later folks built a castle on top, and that was sacked as well. So the entrance would naturally be fortified, and choices limited to restrict where successful attackers could get for at least a short distance past the fortifications. So I came up with this:
Pit, pillboxes accessible only from the second level, anti-magical surfaces, multiple choices all fortified heavily, smoothed-over metal doors, and no cover once you start coming down the stairs. It's cool and fairly unusual in a megadungeon entrance.
But it does restrict options. It means you need more access points into the dungeon, that make sense to be open despite being part of a fortification, and the players are much more limited in where they can go.
Easier access would make it easier to explain all sorts of folks in the dungeon, too.
Having a multiple choices (which of the staircases down into the dungeon do you take?) right from the get-go would been nice.
I don't regret my choice, and the reality of needing to limit movement to limit the amount of prep I needed before we could play made this approach make sense. Plus it makes for some unique issues (the way the players have interacted with the orcs in order to ensure easier access to the dungeon but also conceal their activities has been fun.)
Might Do Differently
It would be tempting to do the megadungeon as a super-dungeon, much like Beedo's Black City. That would make it easier to put very disparate groups down in the dungeon, because they could be very seriously separate.
Wizard Did It
My life would be much easier if I had a Zagyg or Hallaster or W*E*R*D*N*A who'd set the whole damn dungeon up as a test. That lets you explain anything, from crazy puzzles to ridiculous traps. I may do this in miniature but it's too late to do the whole dungeon that way. I could spare myself a lot of headache with a Megawizard in my Megadungeon.
A Bit Of A Trek
Putting the castle a half-day's walk away was fine, and made perfect sense in the game world. But instead of "camp at night and enter in the morning" all it did was have people get up pre-dawn and leave the moment the gates open and explore in the afternoon. Forcing people to deal with the surface at night would have been a nice feature.
The other option would be no trek at all - the dungeon is downstairs, like Undermountain or anything in Petal Throne.
All are good, though, and I don't regret my choice. I would just consider a different one. I kind of liked the walks back and forth to the Caves of Chaos.
Next time (maybe tomorrow, we'll see) I'll take about how I'd run my game differently - different rules options, different game world decisions, etc. Today, it's just how I'd make the maps and labels different in my dungeon.