The switch back to force-directed layout proved to be a big success; the level aesthetics are far better now, as expected, and the hallway pathing is proceeding much more cleanly due to greater locality between neighbors. Here's a 5x5 grid of rooms, looking very fine:
I'd still like to get those rooms a lot closer together, but this is way better than before. The process is also still pretty slow for a level this size, but not so slow that I'm worried; at worst, there could be a background thread generating levels ahead of time.
This seems like a good place to let the hall layout stuff rest for a moment and change gears to something new. I guess I'll get on to those lock-and-key puzzles next! Oh, and I've got to implement a run command; going down those long hallways is driving me crazy. Progress should come much more quickly on those kinds of features, compared to the research project these hallways have turned out to be, so perhaps we can start to have something that feels like gameplay before long.