I Saw the Devil is by no means an easy movie to watch. I think that some people may be turned off by the intense violence of the film, but it’s not violence without reason. Underneath the surface mayhem is a rumination on what revenge really accomplishes, if anything.
There’s a lot of incredible Korean cinema these days and Jee-woon Kim (A Tale of Two Sister, A Bittersweet Life, The Good, the Bad, and the Weird, all amazing movies) is just one of the amazing filmmakers. Joon-ho Bong (The Host, Memories of Murder, Mother) and Chan-wook Park (Oldboy, Lady Vengeance, Sympathy for Mr. Vengeance, Thirst) are also making captivating movies each effort. You definitely want to get on board with these filmmakers. They produce elegant, interesting, and great movies each time and frequently use the same actors (my favorite being Kang-ho Song).
To attempt to prove that I’m just not shilling for the theater, here’s a bunch of reviews you can read about I Saw the Devil:
And while I’m on AVClub, a video they did about I Saw the Devil/Korean Cinema.
Finally, a paraphrasing of a volunteer’s review:
I liked it. I’ve never felt shock, disgust, laughter, tears, being disturbed, more laughter all at one time before.
For a cinematic experience unlikely to be replicated, go see I Saw the Devil!