This is the best adventure I've ever run in any fantasy RPG. This adventure follows the classic dungeon crawl run: your typical small town, with a dungeon nearby. However, under those premises, it doesn't get any better than this.
It is not entirely perfect. If your group is not very experienced, you'll need to downsize some of the later, more brutal encounters (specially if they miss XP opportunities along the way). On the other hand, you'll need to change part of the premise along with some of the handouts for an experienced group, or they'll get the evident clues and rush to the dungeon, missing most of the background and optional events. Also, the adventure has been designed for a relaxed group who won't mind to wait multiple days identifying items, levelling up or researching archives, even with a clear danger lurking nearby. You'll probably want to speed up the timed events a little in most cases.
That being said, the amount of background, the great villains, and the unpredictable nature of the haunts can make this into one incredible run. Like any good horror-themed dungeon crawl, the perils here are overwhelming and can essentially wipe any unprepared group, so they'll need to proceed with caution and study their foes in advance before they dare to jump into the dark paths ahead. The adventure provides plenty of mystery, a constant sense of urgency, an interesting hook, and a ton of roleplaying opportunity. Highly recommended.