Bloody Korean serial killer thriller that's both a callback to older Korean films in the genre and an interesting spin on the body swapping concept.
So here we have something of a Korean version of Face/Off, but with less action and more gory killings. The characters are archetypes well known in this subgenre, such as the determined protagonist cop and a young, snickering serial killer who can't help but laugh as he commits murder. They don't grow or deepen throughout the film, instead you get swept up in the film's fierce pacing and forceful plotting while character development is sacrificed.
The film remains fun enough until the end, even if it constantly reminds you how it could have been even better. Even the gorier scenes feel tired and overplayed. The body swapping conceit is deployed in an implausible, but compelling way, even if it wasn't quite used to its full potential. But it remains the film's main virtue and isn't just a cheap gimmick overall.
Take a look at this film if you enjoy brutal Korean thrillers, but don't expect miracles.
