Spoilers ahead!!
If this movie had explored the complex and intriguing aspect of a severely traumatized and damaged mind, this would have been an incredible psychological thriller. I spent 75% of this movie questioning "what is the main character's tie to this serial killer?" And "Why do we care about her?" These questions sent me down thought processes and interesting plot lines that could have been equally scary and thrilling. Unfortunately, the movie fell short in the final scenes. It's plot became a tired and old trope of paranormal or religious path of horror - I wanted so desperately for there to be some kind of plot that was believable and realistic to fit such fantastic and visually stunning cinematography. Genuinely, it gets boring finding out the things that caused the main character her increasing paranoia, fear, and anticipation comes from a source that isn't even explored until the 3rd "act". Why explore such intriguing psychological avenues and explain it away with someone following Satan? Why not explore the fragmented mind of a severe childhood trauma? Why not explore the psychological aspect of encountering a serial killer at such a young age only to reface the trauma in later life? Why not make it human, realistic, and believable? It would be so much more chilling and terrifying to see the accomplice have been the main character or for the "evil" or antagonist to be a physical being. I feel like this movie fell short in that. It gets 2 stars because the sound, visuals, and acting was the only thing that made it a bareable enough watch through.