The long: Potential module designers of all stripes pay attention.
There are other modules that look better (see anything by Paizo which probably has the highest production values in the industry). There are other modules which are far more clever and weird (Matt Finch’s own The Spire of Iron and Crystal is better). There are other modules that have a better and more thought out back story (though the idea of growing your own god is awfully cool, I think the background for James Boney’s The Chasm of the Damned has a lot more potential and Michael Curtis has done a more thorough job with Stonehell).
The reason why I love this module so much can be summed up in Matt’s own words:
If the Referee has a different sort of sinister enemy in mind rather than toadstool-creatures, it is certainly not required to use Stone Cyst of the Shroom Priests as the sequel. Other than the fact the the insidious corruptors of the Toad-Men have some skills in alchemy, no facts about these deceivers are revealed by the material in this module.Demonspore is actually two separate modules that are connected, but as can be seen above they need not be. Coupled with the fact that Matt has given us three different ways to connect the first part of Demonspore to any extant dungeon/ruin/whatever that happens to be in our own campaign world means that this module wasn’t designed to have a high production value, to be clever and weird or to have an incredible back story. Rather IT WAS DESIGNED TO BE USED.
To me, this is by far the most valuable asset of any module I purchase. While the other three are valuable (and, trust me Demonspore has them in spades) they are rendered meaningless if I can’t actually use the adventure. As a testament to how easy it is to use Demonspore, the very same afternoon that I had skimmed my copy I had seamlessly integrated the entire module into the tentpole megadungeon for my Lost Colonies campaign and it made my own megadungeon better. My players may be exploring Matt’s creation as soon as our next session.
Whether he knows it or not, Matt has stumbled upon the best way for our community to publish a megadungeon. Matt dispenses with any information about where this module is located, other than the fact it is part of a dungeon. He provides several ways that his module connects to the rest of this dungeon. The rest he trusts us with.
Now, imagine if we had available a dozen or so modules written by any number of designers who shared this same format. We, the end users, would then be free to piece them together however we wish in order to form our own unique megadungeon. How much of this megadungeon is our own homebrew and what is published is entirely up to us. The result, I believe, would not only give our generation of gamers the common cultural experience of gaming with broadly used modules, but also allow all of us to have that experience be truly unique to each campaign because of the freedom we would have to use them to construct our own unique megadungeon.
Therefore, I would like to throw down a gauntlet and challenge all of the would-be designers of the OSR to do just this: use the format of Demonspore and produce good quality modular adventures that I guarantee will get used because at least this gamer will gleefully attach them to an existing megadungeon.