I want 2+ hours of my life back

Rating: 2/10 (18 February 2019)

The only reason I'm giving this two stars is because the beginning was pretty good and (as others have noted) it didn't rely on constant jump scenes. The star actors really tried, but nobody could rescue a script this bad.
So much else about the movie was horrible, but not in a true horror kind of way. Apparently the death of a child by decapitation is not even investigated by police and the parents somehow think it is OK that her brother simply drove home and went to bed. Then they are just driving around in the car the next day like nothing happened. Maybe they are just into upholstery soaked in their daughter's blood.
In a movie that touches on mental health, there is not the slightest effort made in that direction at any time. Get a qualified counselor for the family after a mentally ill and manipulative matriarch's death? Nope! Get some serious help after your son accidentally kills his sister by decapitation? Who needs that? Report QUICKLY escalating bizarre of the mother's behavior on the heels of two family deaths? Nah! And on and on and on ad nauseum.
The worst part is that after slogging my way through this swamp of a movie where all the characters are despicable, the ending managed to trump all the movies badness in a just a few minutes. The only way this ending would have worked is if we felt genuine sympathy for any of the characters. However, like so many bad movies where the characters die of stupidity, these characters pretty much get what they deserve for the same reason.