There is a very interesting series of essays on The Alexandrian about Jaquaying the Dungeon, which is a coined term referring to adventure designer, Paul Jaquays, who wrote many well-known old school adventures such as Dark Tower and Caverns of Thracia. Jaquays was known for his non-linear dungeon designs.
Circuitous dungeons with multiple access points and by-pass routes were common features of old school adventures, but have fallen out of fashion in contemporary adventures, which favour linear dungeons that lead the players through each encounter from beginning to end. I find it interesting how these two styles of adventure illustrate how the philosophy of gaming has changed over the years. Old school adventures were all about exploration and they tried to maximize player freedom and flexibility. Contemporary adventures, on the other hand, seem more like frameworks used to link combat encounters together. Rather than being free-form adventure locales, they are more like a carnival ride; you get on, fasten your seat belt and get shown what the designers want you to see, until it's time to get off at the end. There is no getting off in the middle, no detours allowed, nor can you skip any part of the ride.
The Alexandrian compares Jaquays's free form dungeon adventure, Caverns of Thracia, with its philosophical opposite: 4E's Keep on the Shadowfell, the poster child of contemporary linear design, and an excellent example of what 4E gaming is all about - a series of combat encounters leading to a preordained conclusion.
Now, I've always preferred the free-form multi-option approach to dungeon design, not just because this is the style of play that I grew up with, but also because, as a GM, it would bore me to tears to sit idly behind the screen and watch the players progress through a dungeon in which there can be only one outcome. I far prefer to be surprised by the choices that the players make and where those choices take them. But, as I had occasion to discover during my last game session, a Jaquays-style dungeon can bite an unprepared GM in the ass.
My current dungeon is a series of dwarven mines carved into the cratered ruins of the Tuatha de Danann city of Murias, which was destroyed millenia ago by a meteorite impact. The dwarfs lost contact with the mining colony long ago, and the mines have become infested with redcaps. Deep, deep beneath the mines lies the subterranean city of Dragotha and I had always intended that city to be a rest and supply point for exploration of my under-realm of my world - some time in the distant future. The problem is, I placed a secret access to Dragotha in the third level of the mines, because I needed a way for that level's master, Sothiss the necromancer, to trade with the denizens below. I never expected the adventurers to actually find the secret route, nor to venture down it if they did find it and, consequently, I haven't even begun to flesh out the city or the under-realm it inhabits.
I think what caught me unprepared was my assumption, based on a lifetime of old school play, that everyone understands that deeper is deadlier, and that there are no guarantees that a character can survive places just because he can get to them. It was an assumption not shared by my players, and now I'm scrambling to flesh out the centerpiece of a major part of my campaign world before our next session.
I blame contemporary, linear dungeon design, which prevents players from skipping a dozen dungeon levels, and the evil influence of computer games that physically prevent players from accessing areas too dangerous for their level. This creates a false sense of security for players by assuring them that anywhere they can get to is level-appropriate.
Lesson learned: if you provide alternate routes to places expect the players to take them, and be prepared when they do. That way you won't get stuck trying to create a major chunk of your campaign in just two weeks.
Welcome Back to the Labyrinth
"We have been away far too long, my friends," Ashoka declared, his face lit by the eldritch green glow of his staff. "But we have finally returned to the labyrinth whence our adventures first began."
"Just imagine the treasures that lie within," said Yun Tai, flexing his mighty muscles. "Wealth enough to live in luxury the rest of our days."
"And arcane artifacts of great power," added Ashoka his words dripping with avarice. "All ours for the taking!"
"Umm...guys?" Nysa interrupted. "Do you hear something dripping?"