I'm going to preface this with the fact that, while there are probably things I can do to prevent these kinds of scenarios, and that certainly I may have made some bad DM choices, I'm not really asking for criticism or advice (though you can certainly provide either at your leisure!). Nor am I asking for sympathy, though I'm sure many of us has been here. I've had a few sessions not go the way I wanted them to lately, and I feel the need to share the experience with anyone who cares about such things.
-
So I just got back into DMing after several years of just being a player. I tried not to be too ambitious- I took some old adventures I own and updated them for the modern version of D&D and did my best to bring my A game to the table. But things haven't been going quite as smoothly as I'd like- maybe I'm rusty, maybe my group isn't synching with my playstyle (or vice versa). Anyways...
Two weeks ago, my players encountered Duergar in a small dungeon. After a Medium and a Hard encounter back to back, they were trapped by a cave-in. I told them they only had enough air to take a short rest before they would have to unbury themselves, but they came up with an ingenious idea and so were able to take a long rest.
I considered the design of the Duergar sector. It had been set up with roving patrols (random encounter) and there were several more major encounters ahead. But now that the Duergar had the party trapped I realized there was going to be a super encounter that would surely kill them.
This is my first problem- the classic dungeon design is to go encounter by encounter, but it's all too easy to put the entire place on alert, resulting in a massive deadly encounter that is very likely going to be a TPK. I tried to warn the players about this, but, well, I'll continue.
So they extricate themselves from the cave-in, fully rested, having recruited three NPC prisoners to join their cause to find that the Duergar had sealed off the immediate escape route to funnel them towards what I hoped would be a hard encounter with either a short rest before the next one, or a chance to negotiate with the leader to avoid it entirely.
That's not what happened. The party had a rough time with the CR 1 Duergar I'd put in their path, supported by a caster. During the fight, one player thought it would be a great idea to run past the checkpoint, where they blundered right into the second encounter. Seeing a lone, wounded PC, the leader decided to press the advantage and so the second encounter started with some stragglers from the first and the party on the back foot.
They won, but it was a very close thing, and the whole production took up most of the game session (4.5 hours). Everyone was exhausted afterwards (IRL and in game) and while they earned a ton of xp for their troubles, I've been second guessing myself the whole time since. Should I have just let them retreat rather than force these fights? Did I give the Duergar too much of an advantage to prepare for the party? Should I have used weaker tactics or not put the spellcaster in the first encounter? Should I have held back even when the lone PC ran past the chokepoint?
Was the second encounter too brutal? Should I have not used one of the monsters the adventure provided (an Umber Hulk, which proved to be way more deadly than I expected). Is there a problem with the encounter design? Was the encounter builder lying to me about the fight difficulty? Did the inclusion of NPC allies just make the proceedings take longer?