I did enjoy reading this book, and the twists and turns were exciting to follow. The way the narrative plays with and pokes fun at slasher movie tropes is entertaining.

OTOH, it's a little exhausting to be inside the main character's head since she is very paranoid (rightfully so) and her paranoia is always misdirected (otherwise there would be no twists in the plot).

Another downside, the word crazy is thrown around a lot. I think the author tries to treat the issue of PTSD with some sensitivity, but the story establishes a dichotomy between the "good" people with trauma who are handling it "right" and the "bad" "crazy" traumatized people whose issues with drugs, violence, and mental illness are treated as character flaws more than understandable responses to horrific events.

In this book, the many killers, who are mostly men with a couple of exceptions, are evil just because. Characters refer to the killers as monsters repeatedly and very little in the narrative challenges this perception. I have read/seen very few stories that showed a killer as both monstrous and fully human (Hannibal Lecter is a good example, for all the flaws of those novels and adaptations), and this book did not succeed in that. Maybe it doesn't have to? The killer as a force of nature can work, if the focus of the story is on the protagonist's personal journey or if it's some meta commentary or whatever. But the final killer isn't that either, and that's the point (it's spelled out in the text). However, neither were they given enough characterization to be seen as people, so it just fell flat for me. I did like the very last scene though.

if you can overlook some of the more problematic aspects, it's a good read.