I am book-marking these two amazing posts about dungeon map design by Melan
(written 17 years apart!)
Brilliant insights (loops, accelerators, choke points, etc.), and something to keep in mind when generating new maps.
I don't agree with Melan's assessment, or diagram, of Forge of Fury. There are three entrances/exits to the dungeon, four if you count the underwater tunnel in the Dark Mere, which go to three different levels of the dungeon. The Mountain Door level has three potential entrances and three loops, most of which he leaves out of the sketch. The Glitterhame has two potential entrances (three if you used the underwater tunnel) and four loops, of which he depicts only two loops. The Foundry has two entrances to the level and three loops. If you ignore the water entrance, the Black Lake might be considered a railroad (there are two other very different paths to getting there, but they both deposit you in the same general area) until you realize it is just one big room; in my book having a single practical entrance to a room doesn't make the room a railroad. The only linear part of the dungeon is the Sinkhole, which is a small, six-room area with no loops and only one entrance (although there is a trap in the Glitterhame that will drop you there unwittingly if you are not careful).
When I ran this the party entered through the orc tunnel, which effectively meant they were starting on level 2 of the dungeon (Glitterhame). It took quite a while for them to get the lay of the land for the Glitterhame, and they didn't hit all of the encounters in it before they ended up going up to level 1 (the Mountain Door) through the back way. They used the loops in the Mountain Door to their tactical advantage to defeat the orcs, then went back down to the Glitterhame and finished clearing it. They couldn't pick the lock for the door to the Foundry and didn't find the alternate sinkhole entrance, but did discover the key in the Sinkhole - after getting their asses kicked by picking a fight with a roper they were supposed to be talking to. Then they went to the Foundry through the door in Glitterhame, missed eight rooms completely (which was possible only because the dungeon is nonlinear), lost several of their party fighting the duergar, went down the sinkhole to the Black Lake and survived the dragon encounter by agreeing to become its agents.
