What changes I am making to Stonehell
Disclaimer: To any of my players who might read this, please note that while there aren't any major secrets below, this post is broadly speaking not for you and I would appreciate if you skip this one, at least for now.
In general I enjoy using modules when I run games, as they offload a lot of work that I simply do not have the time and energy to devote to during campaign prep. My previous game, Zandan, was a clear indicator of that as writing out that not particularly big dungeon took way too long and way too much.
With the Dungeon Game I want to focus on as little work for myself between sessions as I can manage, hence why I am simply running Stonehell. But I am also me and I can't let well enough alone, so I've done a bunch of tinkering and changes to the thing so far. Keep in mind, I have only barely skimmed level 2 of the dungeon, let alone most of the lower floors. As such any changes made are only to the surface area and level 1.
Overland
I mainly removed things from the valley outside of Stonehell proper. The numerous small caves and micro-dungeons are gone, having left only Coal's cave (because I like Coal), the wolf den and adjoining spider caves to the west of it, the hot spring waterfall source and the former adventurer base on the northern end. That one I felt is important due to the items found within, and hey, it has now become kind of a side-focus for the party to build it up and fortify it into a working base of their own!
The Gatehouse I initially kept empty, adding the goblins as the campaign went on, slowly building up their numbers. The party having now cleared the place entirely makes it secure once more.
Level 1
A common complaint levied at floor 1 of Stonehell is the general lack of treasure. While this is sort of true, I actually think it really depends on what your goal with the treasure even is. Does floor 1 of Stonehell have enough treasure to properly level up an entire party to level 2? Probably not. But it has quite a few spots with decent caches (or the potential for such). As such I have not added much in the way of additional money, but instead added more interesting stuff, specifically magical items (which give XP for retrieving them in my current houserules) and more importantly, several sources of permanent attribute raising. I am growing to like having those around a lot, and I've included two just on this floor, so with luck and diligent exploration they should be fairly easy to find.
I have not done much in terms of changing the actual dungeon layout or factions present, because that starts veering off into "way too much work for me right now" territory.
Enemies
The biggest tweaks I've done are in how I represent enemies in the game. I still am riffing off the ones already in Stonehell, but giving them my own spin (or really, as you'll see, other people's spin!) which I think has paid off quite well so far.
Orcs - Heavily armored pigmen, courtesy of Crow's wonderful write up for their own B2 campaign. They wear chain armor and come in two varieties, skirmishers with javelins and shields or infantry with two-handed weapons, usually polearms.
Overall fairly decent at fighting (though the prevalence of Plate armor in the party makes them less likely to hit), but easily taken down via Sleep spell. They are starting to grow a bit stale as an encounter, so I am likely going to have to change things up sooner rather than later.
Kobolds - Again, many thanks to Crow for the inspiration for these. Small upright vermin, numerous and weak. They are probably one of the most elaborate in terms of random encounter rolling that I have on my list, as half of them are usually armed with ranged weapons (1d4 damage) while the rest use long, but weak spears (1d6). And from there, each half in turn has a chance to have their weapons coated in poison, and further more if there are 10+ kobolds in a group they have some number of firebombs on them.
However how effective all of this is in play I have no idea, as the party quickly figured out they probably don't want to get into a fight with the kobolds if they didn't absolutely have to, so they have been making any effort possible to avoid it. Considering how prevalent the kobolds are on floor 1, that is probably for the best. I am still debating on how straight I want to run the sort of social hub that the kobolds have organized on floor 1, because it feels... I dunno a bit lame, but then again I like social hubs/relatively safe locations in the dungeon, so I am likely keeping it as it would be too much effort to change.
Goblins - Muppet-like creatures from the land of the Fae. Standard B/X goblin statline, save for the fact that any group of 5 or more of them will have access to crude bombs (1d6 damage to everyone in an area, save to negate). I was originally planning on having them have regular bombs (which in my game do 2d6 instead), but with the sheer numbers these guys can appear in that would make combat encounters be a simple matter of the initiative roll deciding whether the party gets TPKd or not, and that just sounds boring to me.
They have not not been too present yet, only really encountered in the gatehouse, but I look forward to having more of them as my players explore floor 1.
Bugbears - These I am super happy with. Based off the old Supplement 1 depiction of them with a pumpkin head (and the Jack O'Bear from Glorantha), the party have run into only one Bugbear so far, last session, and it was already a doozy. I am going for a sort of cryptid and weird vibe for them, strange furry creatures that just do seemingly random shit in the dungeon.
It has the standard Bugbear B/X statline of 3+1 HD and so on, but I also gave it a very nasty special ability. A bugbear can hypnotize 1d3+1 targets every round (save vs paralysis, +2 bonus to save) and those who fail the saving thrown can not act for the round this effect is used. However if the bugbear strikes them while they are hypnotized, the effect ends and that character can never be hypnotized for the rest of the fight.
Needless to say this is quite powerful, so I am cognizant that any future encounters with Bugbears should likely have reduced numbers, at least on earlier levels, because the crowd control effect makes them very, very hard to deal with if even half the frontline fighters are mesmerized for the round. However if the party wins initiative for the given round, the hypnosis isn't used at all, because it would do nothing anyway.
Gnolls - Haven't needed those yet, but I plan on changing gnolls to Pesoglavi. Might need to bump down some of their HD for earlier encounters, but they are not around in the dungeon yet so this is all academic at this point.
Level 2
The party are starting to ponder dipping their toes down there, but they're quite cautious still. I like the stuff already down there, so likely won't mess around with it too much. The only thing that makes me uncertain is the Asylum quarter, because the inmates just give me bad vibes. The idea of "oh these are inbred mentally unstable descendants of the insane people of Stonehell" is some proper fantasy eugenics shit. Like...for one thing how/why are these people able to maintain enough of a faction/society to not only breed but also construct shit, when they are apparently so "insane"?
Not entirely sure how to address it yet, without having to do extensive work. I am likely thinking of just having them still be kind of mental, but blame it on some kind of magical curse or ongoing effect, which to be fair does fit with the broader setup of what is going on in Stonehell, so it's not too much of a stretch. Still - gross, man.
And this is about it, really. I know people were curious about me writing this out, so hopefully this helps you out with your own game! I might edit this or make a new post once I have more ideas/need to change things in the dungeon.