Ghost Houses Of Phylinecra is a gorgeous, evocative, system neutral dungeon about grief. Despite its name, it's high fantasy rather than a haunted house adventure, and the PCs take on the roles of villagers in a small town with an odd local custom.
Structurally, Ghost Houses is 52 pages, easy to read, and has a scattering of pieces of truly gorgeous charcoal artwork.
Content-wise, there's some extremely clever design going on. The adventure takes place across two area maps---one stacked on top of the other. Things from below have affected the map above, and the extent to which this has happened is scaleable with your PCs' group size.
That said, there is sort of a weird first hurdle on the adventure, where in order to progress the PCs have to deliberately walk into a thing that looks like a trap and acts like a trap. For prospective GMs, it's probably worth not having the pool force players to make saves to resist it. The saves make it seem like it's a danger, not progression.
The adventure itself is also less about combat and exploration, and more of a sort of slow, abstract civil engineering project. There are multiple ways to solve it, but fighting isn't very much rewarded, and groups that just want to punch some monsters may find Ghost Houses really frustrating.
Overall, though, Ghost Houses gives me strong Deep Carbon Observatory vibes. It's more oriented around a single emotion than Observatory, but it also feels tighter and more intimate. Plus, it works very well with systems that favor low or no combat, and it might be interesting to pair with something like Trophy.
I would definitely recommend it, especially to folks who like low-combat, more abstract adventures, but it's also got a strong niche as a possible location to drop into an existing campaign.
-Page 11, suggests the map is marked in color (which is hugely helpful) but the color version of the map is not part of the book, and is only maybe referred to as "the fabric map." This feels a little weird.