Bathtub Reviews are an excuse for me to read modules a little more closely. I’m doing them to critique a wide range of modules from the perspective of my own table and to learn for my own module design. They’re stream of consciousness and unedited critiques. I’m writing them on my phone in the bath.

The Cursed Cave of a Billion Bats is a 20 page one-shot or tournament system-agnostic module by Dale Houston. In it, you are drawn into the so-called “Nightmare Cave” with the promise of gold, but will you survive? I received a complementary copy from the author.

The layout is dense, but clear, with smart usability choices like having no locations crossing pages. The only potential problem I can see is that it uses colour coding on the maps to signify climb difficulty, room environment, and the presence of large clouds of bats, which is visually busy and potentially won’t work for all visions — easily fixed by using different shading or dotted vs. bold lines, or something of the like. Both cover by Daniel Harila Carlsen, and the interior art by Perplexing Ruins are excellent, although I’d love to have seen less pages with no illustration. The maps — a three-dimensional cave map and a point-crawl map for those having trouble with the first, are both pretty great — the primary map especially I think does a great job of communicating the interconnected nature of the space without it becoming overwhelming.

Our first page is our hook. and the local village Flotsammar. It’s simple, in a way I genuinely love, with contrasts that raise questions that I hope the dungeon will reveal to me. The three NPCs here have interesting characterisations that make me want to play them, although I’d love for them to have clearer reasons to manipulate the player characters in one direction or another, or bait them into the dungeon. We have 3 d6 tables of rumours, as well, although only 2 of them are on the surface about the Cave, and the other, about the town, would require me to improvise a bit more town than I’d prefer to. Overall. though, it’s a great initial impression.

I mentioned the three dimensional cave map, and it’s well supported by the rules on traversing the cursed cave, which pulls in rules about how light interacts with the bats, and about how to climb shafts of varying difficulty, and also how to secure them, making the dungeon a bit of a metroidvania in terms of making difficult climbs and securing them, or finding alternate ways to the top of hard climbs in order to secure them for quicker traversal. The only misstep I think is that it doesn’t explain these rules directly to the players: I would. It does say “make sure they know the amount of light is important“, but I’d probably include this as something that would be said to the players in town, so that it’s very clear that too much light will disturb the bats. It’s something that could’ve been baked into the world-building, rather than just given as advice.

The module is explicitly a deadly module, which results in a lot of combat encounters, but ones that effort is put into to make interesting — a favourite is the flea knight who leaps in and out of combat. Expect 12 empty rooms and the rest being occupied by either combat or hazards; I’d love for a little more of interest to be in those 12 empty rooms, though. They’re appropriately empty, I think, because rest and space to flee and regroup the difficult combat encounters and bat swarms are necessary for survival, but I’d love to have seen a little more lore parcelled out in pieces throughout them that would allow you to form opinions about Aramor the Mad and the curse of the cave before getting to the final room; this would add some interesting spice to the module that simply isn’t there right now: Why wouldn’t you murder and take the treasure? Random encounters will likely occupy many of those empty rooms, but half of these are combat encounters (most with creatures you’ll see elsewhere in the dungeon, but that aren’t tied to specific rooms), and the others being debuffs with no particular warning. I’d love to have attached some kind of warning or choice to these random encounters. There is one absolutely fantastic one, though, which more heavily looped dungeons should use: A chamber collapse, which renders a room impassible, and will require further exploration. You could base an entire module around this one random encounter to compelling effect, I think.

The book finishes with treasure and monsters. Some very fun and well-described treasure is in this list. The monsters, are well-described, particularly in terms of tactics, but I fear players may have trouble differentiating between all the bat-themed creatures. I also wish the flea-themed creatures had been given a bit more space, because they’re cool — is there a culture of flea-people? I want to know about them! I’ll have to look more into Houston’s other work, though, because the monster stats have a few features I really like, pulled by a variety of potential sources. As well as typical HD, AC, and Movement, they have a mien, ferocity, and weaknesses, as well as “encounters” which describes why you might be meeting them. This is cool stuff, although it would benefit from clearer description — it’s clear that Ferocity is effectively morale, but I don’ t know what Ap or Threat necessarily means.

Finally there’s a score sheet, because this is a tournament module. I, relatively recently talked about how I wish there were more tournament modules with score sheets: This slaps, and makes the module far more playable, particularly if they know at least roughly the score sheet, which will push them towards even more foolhardy choices.

Cursed Cave of One Billion Bats is a really cool, one-shot module, with a lot of cool design choices. At the table, you might want to make sure your players are excited about high lethality, combat intensive play, and there’s not a lot of lore or puzzle-like inclusions to keep those who aren’t engaged. If you were to run this at a small con with a few tables, the tournament score sheet would make for a lot of fun. In a lot of ways, it’s a few strong steps towards meeting modern module expectations with some very specific old-school sensibilities that are rarely considered. I really liked Cursed Cave of One Billion Bats, and if you’re looking for a lethal one shot or are interested in something to run tournament style at a small con, I’d take a look.

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