I ran it this past weekend, went well, though some things didn't really make sense and I significantly modified a number of things, as noted below. In the end, the "skeleton" of the adventure was enough for me to work with well and run a good adventure, but there are some genre issues as well as things that weren't really thought through, as noted below.
****WARNING - SPOILER ALERT****
A few things I changed or were issues:
1. The town that is rebuilding itself - I scaled the "magic" of this way back, such that the PCs noticed the scraping sounds of stone on stone and caught glimpses of movement out of the corner of their eye, but couldn't observe anything directly, make it more spooky and less outright magically appearing.
2. The ghost - I dialed this back as well, made a shimmering apparition appear, and hauntingly called out a warning to the PCs about stopping the rise of the horror, instead of some sitdown conversation with a ghost.
3. The battle for the horror - This was not really thought out well in the module. The module expects more than 1 brother might show up, but only really describes what happens if 1 shows up - Zuleyeh appears, embraces him, and enters him, but what happens when more show up?! Plus, the time involved with ritual to determine the controller or split makes no sense, as during that time, PCs are likely to be fighting. Alternatively, if the brothers arrive with significant forces and/or with the PCs captive, then they will realize they can't stick around and fight and should just flee (which is what my PCs did). Finally, the amulet of shifting skies really seems pointless - so what if the PCs find it and keep it from the ceremony? The horror will still enter one or more of the brothers and make them crueler (even if the brothers dominate), so the PCs actions to keep away the amulet would be pointless.