First and foremost, much of this movie borders on, for lack of a better word, the obscene. There are plenty of scenes that bring to mind soft-core pornography, and the violence is incredibly gory and at times, over the top. Some of the actions performed on screen will make most viewers squirm uncomfortably, while a vast majority of those that aren't will let the audience's mind drift to some very, very scary places.
In short, its a visceral thriller. The movie is essentially driven by both lead characters trying to inflict as much pain and terror in one another as possible. Unlike most serial killer/crime thrillers, both the two characters collide (in violent, brutal fashion) with one another many, many times, leaving each other bloodied and eager for the next encounter. During these scenes, the movie takes on an unexpected action tone, with plenty of engaging fights that include knives, scythes, screwdrivers and in one scene, a fire extinguisher. In between these scenes the audience is shown the full depravity of the serial killer's psychopathic nature, who pretty much succeeds on setting the bar for on screen insanity.
If this sounds like a mindless action/thriller summer film, you'd be mistaken. Both Choi M.S and Lee B.H deliver great performances, with Choi in particular acting disturbingly convincing as a completely unhinged maniac. The plot, although somewhat predictable, is nonetheless entertaining and once set in motion, incredibly gripping. There are plenty of cheap "boo! gotcha" scares, but some scenes are masterfully crafted to generate a LOT of tension. Believe me when I say that there were plenty of scenes where you could literally see that the rest of the audience wasn't even breathing, much less moving. As mentioned earlier, the action scenes are shot surprisingly well, and there's a certain pleasure to be derived from watching the hunter become hunted... and in such an exquisite, effective and merciless manner.
On an aside, the movie seems to have remake potential with Hollywood production. Perhaps starring Will Smith and Robert Downey Jr. (as a serial killer? wouldn't you be terrified?), with maybe... Danny Boyle at the helm? Hopefully the movie does well enough in its release to receive any considerations.
