I am running a heavily-modified version of this for my gaming group. We just had our first session and we're about one room into the underground, since the majority of the time was spent carousing and Doing NonCombat Character-Building Stuff(TM).
Altered assumptions:
- In order to fit into my campaign setting, the main "horde" type monster outside was Rock Mites, not Zombies.
- In the tavern, one of the NPCs was a severely depressed elven woman who was posted to the local dwarven tribes to do an apprenticeship in gemcutting, since she was good with amber. She ended up drunk, but her sack of uncut gems is also a potential distraction for the Rock Mites, causing them to clump up along whatever portion of the outer wall is close to her interior location. The PCs could use this trait to lure the Rock Mite hordes briefly so they can climb down to the stables and retrieve items.
- The underground tomb is the burial place of a dwarven resistance leader. It was sealed away for centuries but recently part of the underground sealing wall has collapsed, allowing its guardian-themed magic to escape and causing the hordes of rock mites to animate.
- Underground monsters include: Obsidian Jaguars (re-themed to be Granite Wolves), Stone Golems, Rock Trolls, and the main boss are two well-equipped dwarven Draugr (the resistance fighter leader and his brother in arms).
- The living dwarves are a bit cross with the human government, and there are tensions. Once drunk, they often utter a dwarven curse (which translates to "leave our land" and happens to sound a bit like a grammatically nonsensical English term of abuse). Underground, there are ten carvings around the draug's resting place that shows this exact same ancient curse. If the PCs can find and deface them all, the magic fades and the rock mites will disperse. Or, they can also lay the draug to rest permanently.
I've noticed that one potential problem in my PC-to-challenge calculation is that two of my players are playing finesse-style assassin types. Unfortunately, the enemies are mostly stone-based enemies, so DR is high and most of them are also Homogenous, meaning crits and location-specific hits don't really do much.
I'm trying to build in some monsters (e.g. golems and draug and minor undead) that have somewhat scary or inconvenient weapons, so that even though the swashbuckler and assassin don't do full
damage against them, they can still disarm or sunder the enemies' own weapons (something you can't really do against, say, a Rock Mite or an Obsidian Jaguar whose natural weapons are stone).
I'm also looking to place multiple traps in the area so these sneakier types get their time in the sun.
One other change: the watery chamber of "You All Meet At An Inn" no longer has a lever to pull. Instead, I've placed a few hanging stalactites at the upstream end of the chamber. A perceptive PC could notice they look pretty fragile, and could be brought down with enough impact. This will block the upstream flow and cause the river to fall in level, making it much less threatening. (The river's monsters - leeches and water snakes - are both still unchanged in my drafting, so there's
something living that our finesse-built PCs can hurt.)