This review may contain spoilers. I can handle the truth.
Excellent cinematography, sound design and acting.
The movie took me for a ride where you were never quite sure what would happen next.
It deals with a lot of subjects like grief, ghost, occult, sleep walking etc.
But the final interpretation I got from this movie was, death/some spirit was trying to snatch Rebecca Hall's character from life. It suggested her husband to kill her, her husband tricked death by studying some occult practices and killing girls who looked similar to her to protect her life. In the end, the husband decided that the best course of action would be to kill himself.