Just like with encounters, having a framework to help guide the construction of an adventure is helpful. There are, however, a much smaller number of types of adventure than you might think. In fact, the overwhelming majority of adventures are one of three types, and one of them isn’t very good.
The first adventure type is also the most classic, the dungeon. A dungeon is fundamentally a series of encounters connected by decisions about where to go next. Traditionally those decisions are defined by physical barriers, but you can also use trails in a forest or other wilderness area, or city streets in a city amidst an invasion, or a network of teleporters that connect rooms hundreds of miles apart from one another. What makes it a dungeon crawl is that you enter a room, have an encounter, and then make a decision about where to go next. We’ll talk more about how to make a good dungeon later, but when we say “dungeon,” we’re referring to this broader category, not just subterranean labyrinths.
What separates dungeons from other adventure types is exploration. Exploring a dungeon means wondering what’s down the next hall (depending on how lethal the dungeon is, this wonder may provoke anything from excitement to dread and often settles in the middle to a sort of hopeful apprehension). A dungeon crawl is best suited to adventures where the goal is to find something amidst a bunch of other things. That something might be spread around all over the place, like “treasure,” it might be in one specific location, like “the lair of the boss,” it might be in one place but moving around, like “the captain of the hobgoblins raiding this town,” it might be basically everywhere but you have to get all of it like if you’re trying to clear a dungeon completely for use as a base of operations, but whatever it is, players are trying to find a thing, and sometimes then want to do something with that thing (kill it, shove it in their pack, whatever).
The second adventure type is the mystery. While games like Call of Cthulhu and Dark Heresy have characters investigating mysteries that are typically some kind of actual crime, like a detective novel where the culprit is a shoggoth or an evil space wizard, a mystery is used any time characters’ main goal is to know a thing they don’t already know. The heart of a mystery is just a trail of clues leading to a conclusion. You can use a mystery adventure for tracking goblins down to their lair, finding blackmail material on a reticent member of the king’s council to pressure them into voting your way, or finding the location of a long lost magical artifact. Mysteries have a bad reputation in certain RPG communities because they are hard to run well, and a poorly run mystery is definitely extremely tedious, but they’re plenty of fun when done right, and we’ll talk about that further down.
The main difference between a dungeon and a mystery is actually quite small. In a dungeon you are searching for something in a small, well-defined space and you can search that space systematically. In a mystery you are searching for something but the list of potential hiding spots is too vast, or else the thing you’re looking for is abstract or otherwise insubstantial so a physical search doesn’t make sense to begin with, so instead you have to deduce what you’re looking for from clues. It’s a relatively small difference and yet it changes virtually everything about how the adventures are constructed and played.
The third adventure type typically encountered is the railroad. The GM designs a certain set of set piece encounters, the PCs encounter them one after another, and the GM fudges the encounter if it looks like it’s going to turn out the wrong way. The players have no significant decisions to make, are never at any real risk of failure, and at best can only pick from a very limited selection of goals (i.e. help Alice get the MacGuffin or help Bob get the MacGuffin). Often their goal is pre-determined entirely, and by definition of a railroad, their approach is also pre-determined. A lot of advice is given on how to make a railroad appear to react to player choices without actually changing the pre-determined list of encounters at all. Without real choices, there is no challenge, so for purposes of this guide it is strongly recommended you avoid this kind of thing.
We’ll be adding on two new adventure types on top of the dungeon crawl and the mystery, and those are the wilderness journey and the mass combat. The wilderness journey has some similarities to the dungeon crawl (and you can actually use a dungeon crawl system to run a wilderness journey if you want), however each room contains an encounter table instead of a specific encounter. After one encounter from that table has been completed, it is crossed off the list, and from now on whenever players roll that encounter, they scroll up or down in the direction of whichever encounter is their ultimate goal, usually the exit from one area of wilderness to another. Another big difference between a relatively small scale dungeon crawl and a wilderness journey is the ready availability of long rests and the relative difficulty of retreating to the safety of a town.
The most important difference, however, is that the sheer amount of space between encounters in a wilderness journey renders many of the most interesting parts of a dungeon crawl meaningless. It’s rare that a wilderness will be any kind of labyrinth, and the question is usually not “which one of these paths leads to our goal” but rather “which one of these paths is the fastest or safest route to our goal.”
The mass combat is a battle writ large. Units trade blows with one another on a strategic map and every round of combat can contain at least one, sometimes more encounters for the players. A mass combat is for the most part a war game and should be used sparingly unless your group is the sort that would be happy to sit down and play Twilight Imperium.
Defeat Without Death
D&D has a long history of death being the only meaningful way for a party to be defeated. The protagonists of other media get defeated without being killed all the time. Hollywood’s stock three-act structure involves an act two down beat where heroes are defeated, and it almost never involves one of them being killed, let alone all of them.
D&D 5e already has a few mechanics in place to make death unlikely. Death saves mean that even a character who is completely isolated when they run out of hit points won’t necessarily die. A TPK will likely result in some actual deaths, but many characters will make their saves and revive. Declaring that all PCs make their death saves and revive a few hours later whenever they go down for any reason wouldn’t be any more of a reach than making short rests five minutes and long rests an hour (an optional rule presented in the DMG). Characters stir back to life, left for dead on the battlefield, some of them dragged off into piles of corpses not yet burned, others lying in a ditch where their “dead body” was shoved to make room for soldiers marching into the town they were trying to defend, some awaken where they fell, and now the scattered party must regroup in the ashes of their failure, the town burned, the good king captured, and the forces of evil triumphant. Everything valuable, most certainly including any magic items that weren’t concealed or disguised somehow, has been looted by the victorious enemy and is now being either used by powerful enemy lieutenants or else, if they can’t use it themselves, stored away as a trophy and treasure.
Just because no one’s died doesn’t mean that PCs haven’t failed, and indeed, the fact that the failure state isn’t immediately story-ending (if not game-ending) means that the stakes are much higher, because the GM has no reason to be extremely reluctant to allow PCs to fail. Darths and Droids jokes about how the fact that PC failure means PC death means that any potentially lethal situation is one in which PCs can use their own imminent deaths as an ultimatum to get the GM to bend the rules for them. Not only that, if PCs are facing death and the end of the story for any failure, they are strongly encouraged to try and fast talk the GM into accepting whatever insane plan they’ve concocted to get them out of consequences scot free. The incentives are much weaker if the PCs are looking at a setback rather than the loss of their character.