Ben's prize for making me laugh the most in the caption contest was to pick a module for me to review. He chose D3, but it's hard to review D3 without giving a look at D1 and D2. So let's do that.
I'll start today with D1, but with references to D1-2 where D1 was lacking important information.
This review does contain a lot of SPOILERS.
For more reviews see my reviews page.
D1 Descent Into the Depths of the Earth
by Gary Gygax
D1 is the first follow-up adventure to the G-series of modules. It consists of an underground wilderness hex crawl, aided by a map found on the drow in G3, looking for the source of the drow. Along the way you can encounter all sorts of creatures now associated with the drow and the underworld wilderness - bugbears, trolls, gargoyles, beholders, mind flayers, and more.
The adventure largely consists of navigating a series of primary, secondary, and tertiary passages - from the easier to traverse but also the busiest with wandering intelligent encounters to the hardest to traverse but less traveled. Along the way are several set-piece encounters that contain valuable intelligence, equipment, and so on to enable the group to continue. Or to expend resources uselessly, depending on the encounter. In what feels like typical fashion for high-level AD&D adventures, the first thing done is to nerf travel magic so the PCs have to stick it out in a big crawl - no teleporting to the surface for supplies or reinforcements or escape.
One thing I found especially interesting is that "the treasures placed along the way at aimed at supplying [the PCs] with the force necessary to continue" - it's a dangerous setting the loot is placed in a helpful, not adversarial way. I'm not sure I really noticed that in recent years, but it does play into how we often stocked our dungeons - with stuff we wanted the PCs to have so they could go on to the next module we wanted to run! Still, a little earlier Gary Gygax writes "Neither help by suggestion or inference nor hinder in any manner not called for." So it's no friendlier than usual, either.
The adventure, as written for D1, has some problems. One of them is that one of the encounter areas (the larger crossroads of caves) is never actually placed on the map. It seems pretty clear were it should be, but the module doesn't actually indicate where it is. D1-2 does a lot to clean up this mess, by putting in a note explaining where the encounter is on the GM's map, but it doesn't do it perfectly. It seems pretty clear the map intends the second encounter area - the large cave complex - to the in the doubled hex areas on the map. But the passages simply don't match up - the small-scale map features three large passages and spans a few hundred feet. The large scale map shows four primary and one tertiary passage. D1-2 attempts to clear this up by saying there are two secret exist - but if you match map to direction, one of them is a secret primary passage. The small scale map just doesn't support that. It just seems like the encounter area was drawn without reference to the large-scale map or vice versa.
The mind flayer "advanced base" is also odd to me. It's in a narrow primary passage. No one can pass by without coming within 30-40' of them. Does this mean every drow caravan headed this way, every drow elf in G3 walked right past the mind flayers? It seems like it must be so as you have normal chances of encountering drow activities in the area. Unless they also took a treacherous and longer detour around it, of course, but that's pure speculation.
The progression of this adventure is interesting. If the PCs follow the map and brave the mind flayers, and defeat them, and can prove it, then there is a 90% chance the drow give them passage. It doesn't make an exception for surface elves despite their mutual hatred, so clearly, if you mess with mind flayers they'll give you a pass for racial emnity. There are plenty of areas you could sneak right past.
Now, couple that with the encounters in D1 and D2 - if you clear the mind flayers, there is good chance you just pass through D1 with nothing further to fight except wandering monsters (some of which can be very tough indeed). You can pass the bugbears and trolls and troglodytes. D2 features the Shrine of the Kuo-Toa, but honestly, you have to try to start trouble there to get it. You can just pay a bribe and move on. In other words, it's quite possible this is just a sightseeing tour with wandering monsters until you get to D3 and find your target. That isn't bad, actually, but it does mean most of this adventure is probably wasted detail, like the HP of the townsfolk in T1 The Village of Hommlet or the specific guard counts in B2 Keep on the Borderlands. Just nice to know.
How is it for GURPS?
This would be well-suited for GURPS Dungeon Fantasy or the DFRPG, in my opinion. Most of the "required" fights are interesting mixed-foe fights, but don't have huge numbers. The difficulty in crowd control compared with AD&D means stealth, not storm, would be the better way to deal with almost everything. And the lack of Alignment means dealing with the drow can be a much more practical affair. I'd at least consider making modifications to the map, or just re-drawing sections of the wilderness map.
I ran D1 (as part of D1-2) at least once for a post-G3 AD&D campaign. We pretty much just skipped to the main encounters - and if my notes on the adventure are any indication, that meant the Mind Flayers and the larger cave areas. I carefully noted HP for every single wandering monster possibility, but I don't have any notes in the module to say they encountered them. Back in Elementary School and High School we tended to skip to the stuff we liked.
I know I never noticed the map weirdness I mentioned above - the "advanced base" that's within a few feet of the only path the drow can take (yet they leave it alone), the lack of clear mention of where one encounter is, how the large caves don't match the large-area map, wondering where those drow caravans are going, and so on. We just played them as straight-up dungeons. Still, I find these really interesting adventures.