Raphael Georg Klopper’s review published on Letterboxd:
Well, I guess that's how Koreans handle shit. I mean, the director Jee-woon Kim would never just make a simple cop investigave thriller out of this plot, wich he does in the first 20 minutes or soo just like if this was the Korean Mystic River, by genuinely teasing the unexpected tragedy that invades this character's life in such a brutal level. But all just to turn things up not even half-way through the film and also make this a straight hardcore and small scale action thriller in the midst of his somber horror tone. Not sparing at any punches on that regard by delivering some thrilling and brutal physical confrontations that do overcock a bit on the shaky department on some of the brief car chases, but compensate in some unstop and truly kickass brutality that would make The Raid run for his money. That maybe serves up to soften the other disturbing and time-consuming sequences of cold-blooded murder that creates real shivers down your spine and gave me the scariest jump scare in years right at the begining.
But all getting married in a oddly beautiful mix of genres that I Saw The Devil expertly creates while reveal its true facet of a revenge thriller after some constant twists start to happen through the movie while you see the predator actually starting to become the poor alive pray of a man hungry for payback. To the point where you almost have an Alex De Large kind of treatment towards it, a despicable character that is getting soo much hamered by its sins hauting him that you can actually start kind of feel a minimal dose of sympathy towards him. Also thanks to a magnetic and charismatic performance from Min-sik Choi in his most iconic role since Oldboy. But all just to be boged down at the end where we see the living encarnation of the movie's tittle is reflected on the villain's face and abble to shake your spine, and consolidate him as one of the best villains of the genre easily.
Even if the outrageously questionable actions from the character of Byung-Hun Lee really keeps you question through out the film who is the real devil of wich the movie's tittle refers to, the one that takes pleasure and satisfaction out of the suffering of its victims or of the one that seeks to obtain satisfaction by torturing the torturer. Kind of adding both a tragjc comedic tone and heavy laired drama into the mix. Exatcly where Byung-Hun Lee proves to be a true badass, even whorty of the level as guys like Jet Li or Jackie Chan themselfs, in the way that at the same extent that he shows to know how to kick some real ass, he also can act and perform all the anguish feelings that his character is going through.
By the end delivering the same old teaching about revenge isn't gonna bring nothing beyound only more suffering, but all taken to the level of a visually brutal tragedy where no one gets compensation out of a world where the devil habits in all man's actions commanded by blinded hatred. An insightful dark study of violence awaken by human nature, at the same time that it is a mainstream action thriller where its sort of vigilante protagonist go on a witches hunt for all the surprisingly big number of psychopaths that live in South Korea, that will shurely make you think twice before going drive around night time.
All that in this same unique kind of movie. Is that why some many people praise this movie as being the Korean Se7en? Maybe, but its darn good indeed.