Time Out says
This visually sharp, sporadically successful mix of ghost-story and psycho-thriller lunges from set-piece to set-piece with scant regard for logic, characterisation or narrative structure: flashbacks and dreams abound, threatening to swamp the film. So eager is Ahn to shock us every 60 seconds or so, he forgets suspense works best when tension’s wound up slowly. If the film made more sense, it might be interesting to examine its articulation of anxieties about parenthood, infidelity and sexuality in the the young, and how they may be affected by the new lines of communication opened up by mobiles. But as it only scratches the surface of these themes in the hope of something scary arising, one’s left wondering whether the kid playing Yeong-Ju might really be possessed (she certainly looks as if she is), why Ji-Won moves to an isolated house, and why she doesn’t just dump her bloody phone. Then again, she’s a journo with plans to write a novel, so irrationality’s probably inevitable.