Scott Wise’s review published on Letterboxd :
This is a technical masterpiece of filmmaking ingenuity. Told largely from the first-person perspective of a true maniac, this film does a fantastic job of immersing you in the bent life of a killer.
But the movie itself represents the hoakie geotesquery of B movies that I personally have a lot of trouble enjoying. This is exceptionally well-done camp. But it's camp, and than means an amount of detachment from reality in a direction that I find grating.
Elijah Wood and the cast all seem out of their element, possibly because they are acting entirely to a camera, or possibly because the dialogue is infused with a certain amount of cheesiness. Arnezeder's Ana does the best job of presenting an authentic, compelling character, but the film does a pretty bad job of extrapolating on her and giving us enough background to really engage.
Overall, this is a feat of effects (both practical and digital) and worth seeing on a technical level. But unless you like over-the-top remakes of already campy films, you might just skip this one.