I am currently using this at my table. The table rolling is a bit difficult and time intensive on the fly (although it's worth it for the emergent situations) but I recently automated most of it, which should solve that problem.
This supplement is a beautifully creative and mentally stimulating work of art. It is guaranteed to be an interesting destination for your players, and is easily worth it's $5 pricetag.
However, I have 3 minor complaints.
- The most confusing issue is that it seems to liberally mix up the white and grey librarians throughout the text... in several places making the white librarians the shepards of the dead, but elsewhere it is the grey faction. Likewise, there are grey librarians tending to the calculator, but white tending to the sheol computer... it's self-contradictory, and could be easily fixed.
- The treasure available throughout the library seems a bit biased toward being overpowered and way too plentiful and random for an OSR product. (though that's easy enough to fix on the fly, I guess). It's as if no-one gave thought to balance. For example, let's run the numbers on searching the first room of the library. Searching in any room (even the entrance foyer) for 1 turn gives a 20% chance (!) of finding some sort of valuable treasure. Right off the bat, that treasure has a 45% chance of being a magic item. Your level 1 player has a decent shot at either a +2 (!) weapon with some auxilliary magical property, an eye that sees through walls or invisible, robes that see in the dark, potion of invisibility, etc.
- On the other hand, once you reach a certain depth (15), you are vastly more likely to get less valuable treasure as you go deeper because Cavegirl introduces a d20+d10+d6-2 mechanic that (unintentionally?) introduces a curve biased toward results landing in the middle of her table, instead of equally weighted. Normally it wouldn't be an issue, but that same table is designed to linearly scale the deeper you go (higher rolls generally better). The depth mechanic is a brilliant idea, but the execution of it doesn't seem to have factored in any probability curve, particularly for the treasure table (which is the OSR is the most important table to your PCs :D ), but paradoxically - also for the encounter difficulty.
That all said, overall, I'm very happy with this product, but Cavegirl may want to correct the several inconsistencies for clarity (particularly the crucial librarian faction mixup). I understand this is a cup-of-coffee priced product from a lone author. She is obviously very creative and must be a joy in person :)
[4 of 5 Stars!]