It's a film that stands out for its ability to create an eerie and immersive atmosphere. Kim Jee-woon's direction is masterful, with an impeccable use of tension and suspense that keeps you on the edge of your seat. The narrative is complex and layered, inviting the viewer to unravel the mysteries and relationships between the characters.

The performances are outstanding, especially those of the two leads, who manage to convey a deep emotional charge and vulnerability. The cinematography also deserves a special mention; each shot is carefully composed to heighten the sense of unease and beauty at the same time.

However, while the story is captivating, it can be somewhat confusing at times, which may leave some viewers a little lost. Still, the film manages to be a memorable experience that stays with you long after the end credits roll.

Overall, it's a standout work in the psychological horror genre, with an execution that almost borders on perfection. A film that undoubtedly deserves its place among the greats of Asian horror cinema.