It was a pretty quick read once I got into the story. I enjoyed the story overall, though some of Emma's thought process was a bit repetitive to read.
Some of the ending twists landed, some didn't.

I liked Chet's motivation and think it made sense, amd Viv's twist at the ending was interesting to say the least. Lottie's twist and the asylum backstory felt like they stopped short, like it didn't quite go there.

 
Which leads me to how there was a lot of build up in this book for some spooky, dark, and teisted things but it stops short. Which is good news for those thrillers readers who still want the twists and turns without the super heavy ending. For me, it's spooky season so I was willing amd ready for it to run completely with the darkness. 
One side note, I really enjoyed the setting and environment. It was well developed and I could easily visualize what everything was supposed to feel and look like.