This was rather disappointing.
The ironic thing is, Ryukishi07 had written “a horror VN about curses” before - that would be the question arc of Higurashi - and it was a thousand times more interesting, because the game had you questioning the true nature of the curse at the very least until the end of Questions Arc. Iwaihime has no mystery to it. Only a bunch of one-dimensional characters (excluding main character, who is quite literally a perfect being), a very straightforward problem and a solution to it that can only be described as a string of asspulls.
Iwaihime isn’t even a proper horror. Most “scary” moments boil down to physical/sexual violence - which can be repulsive, but not scary. There is no tension or anything. Compare that to early chapters of Higurashi or Umineko - the difference is like night and day.
Maybe people are right to worry about that Silent Hill spinoff that Ryukishi07 is working on.

Ryukishi07's ̶S̶a̶y̶a̶ ̶N̶o̶ ̶U̶t̶a̶ Iwaihime is....a weird one. There's A LOT of moments that just feel like gross for grossness' sake, multiple female characters whose backstories revolve around sexual assult and like....maybe I'm crazy but a weird amount of fatphobia??? Plus the protagonist is pretty bland overall, and you've got the trope where everyone else immediately falls in love with him and says how great he is all the time

Now ALL that being said, there's something about Iwaihime that I found very compelling all the way through, and there's definitely moments of Ryukishi07 brillance sprinkled throughout, with some good mysteries. I also enjoyed all the female characters quite a bit, despite being kinda over how often visual novels use sexual assault to show that they've suffered, although Riria is a bit repetitive

My recommendation comes down to whether the game is on sale, I think