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.
I know you said you're not looking for feedback, but I'm glad you posted this. I'm a newer DM, and I really like to try and analyze my sessions as well.. Look for lessons to learn from and what not. So I'm going to reply to some of the stuff you wrote about mostly as an exercise for myself, but perhaps it help you as well. I hope you don't mind.
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.
What did they do that was so ingenious, if you don't mind me asking? I'm curious because I've tried to take a very "Go-With the Flow" kind of approach, and I'm often in a position where I'm allowing myself to be pleasantly surprised by my party.
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.
I ran into this recently too.. In "The Sunless Citadel" my party sided with the Kobolds, and recruited a squad of six kobolds. This is fun.. But ultimately something I think I'm going to try and prevent in the future.
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?
See this is tough. You try very hard to make your dungeon seem like a logical, realistic ecosystem. These creatures are living here, and working here. The Duegar want to win.. So it makes sense that they would prepare, knowing there is a band of adventures here to take their stuff.. Especially if they have 8+ hours to do so. I'm currently wrestling with this myself. My last session ended with the party retreating after a winning a tough fight to rest and lick their wounds in the Kobold controlled portion of the dungeon.. So this should mean that the Goblins will notice their guard forces have been murdered, and they will prepare to retaliate, or at the very least bolster their forces right?
As far as doubting the spell caster, I wouldn't.. Having spell casting mobs is a must in a lot of combats for me. It gives the encounters so much more variance, and it really amps up the stakes for the party. They have no idea what spells this enemy has in the tank, so every turn they let the caster survive is a very risky roll of the dice. It's too fun to not include.
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?
Encounter builders are tough, because they can't really factor in the dice. A deadly encounter can end up trivial if the party rolls fire all night while you're stuck throwing single digits, and visa versa.
NPC allies do make proceedings take a lot longer.. Just more bodies in general. Unfortunately with the way the action economy works bodies are more important than HP it seems.
Should I blame the PC's for not coming up with a better plan (I'd told them they'd need one last session)? When one player ran late, should I have weakened the encounter? I have the power to adjust things "off-camera" as it were, if the players don't know how many foes lie ahead, I can always swap things around. Whether or not a DM should has always been a hot debate- whether to treat the game as a game or a world that doesn't adjust itself to the players- I try to use a combination of both approaches, and even if the PC's know exactly what lies ahead, Orc #6 could always be sick that day, desert, go to the bathroom, or slip off to hook up with his lady friend, right?
I have trouble with this as well. The world doesn't revolve around the PCs, or at least I don't think it should. I had an early session where my party was missing a player, and they got into a really tough fight they barely escaped from with their lives. One of the players asked me after the fact if I re-adjusted the fight to accommodate for them being down a player and I truthfully answered no. I actually hadn't even thought of it, and in hindsight I'm glad I didn't.
Maybe Orc #6 could have been sick that day.. But at the same time.. The Orcs don't know that Randy the Wizard is going to be sick that day either right? If they think they should have four bodies guarding the door, they have reasoning for that, and "We expect this party of five players to show up. If one of them doesn't Dave can take a half day" doesn't jive with me.
I don't think there is an answer here- no matter how carefully you plan, things can go wrong- you're rolling dice, and in the heat of the moment, both the DM and the players can make wrong decisions. Maybe I should take pride in the fact that the players did succeed, and the game can proceed- certainly, a TPK would have been the worst possible outcome!
But at the same time, when I only have 5 hours every two weeks, a session like this doesn't feel like it's really advancing the adventure either. Anyways, that was my experience
I agree with this the most.. Ultimately I think the party
almost dying but squeaking out with the win is the best case scenario. That's heroic fantasy in my mind.
But yeah.. I'm having a heck of a time right now because we've had two back to back sessions where I feel like we've made zero progress just because of these crazy fights taking up whole sessions. Session three is likely going to be the same.. And I'm hoping we can finish the adventure in the next one. Part of me wants to make the fight easy and quick to move along the story, but that feels like it would be less satisfying, albeit in a different way.
I don't think you did anything wrong. Hopefully in the grand scheme of things this adventure will be memorable for the players because it was challenging and they were successful, and they will forget about it being long and potentially a little tedious.