The average person doesn’t enjoy viewing rape, torture or murder, which is why those moments in film are always shocking and typically used sparingly. Since the line is fine between artful and tastelessness on this subject matter, filmmakers who aren’t simply out to shock and revolt viewers are wise to tread carefully. In I Saw the Devil, director Kim Jee-woon seems to have found a unique formula in delivering awful brutality that will push audiences’ limits, but amazingly never break them.

Soo-hyun (Lee Byung-hun) is a government agent with a pretty fiancée who is pregnant with their first child. On one snowy evening, Soo-hyun’s fiancée finds herself stranded with a flat tire and also the prey of Kyung-chul (Choi Min-sik), a brutal serial killer who dismembers his victims. After the discovery of his fiancée’s body, Soo-hyun descends down a path of bloody revenge as he tracks down and eventually confronts his fiancée’s killer. Unfortunately for Kyung-chul, Soo-hyun isn’t content to simply take Kyung-chul’s life – Soo-hyun wants to destroy it. Soo-hyun, however, will learn that revenge has a habit of affecting more than its target.

I Saw the Devil is a pretty straightforward moralistic revenge tale. The protagonist suffers through a ghastly circumstance that forces him to decide if he is willing to become a monster in order to hunt a monster. While this basic story and dilemma has been told many times, it’s the presentation of I Saw the Devil that truly sets it apart. This film is one of the more brutal films in recent history.

Extended scenes of horrific death and dismemberment are commonplace in war movies and torture porn films, but also seem different than how I Saw the Devil wants audiences to appreciate violence. In war films the gore is justified as the realities of combat. In torture porn the gore is cartoony and fantastical – purely for shock value. For the most part, the violence in I Saw the Devil simply is and is presented as such. Shots only highlight the gruesome acts when necessary and murderers seem to take as little joy as possible out of the killings. In one scene, Kyung-chul goes through the laborious motions of hacking a fresh corpse apart and tossing limbs into a basket. At first, it’s shocking, but the mundaneness of the presentation helps settle viewers’ revulsion, while also simultaneously filling them with disquiet for being able to accept what they’re seeing. It’s an effective dynamic and one that director Kim Jee-woon seems to wield masterfully. By the end of the film, most audiences will feel at least a little unsettled at their own desensitization to violence and viscera.

Choi Min-sik carries the film wonderfully and manages to keep audiences in rapt attention without eliciting sympathy. His performance is raw, natural, explosive and terrifying. He can also be ironically funny and audiences may find themselves laughing in spite of themselves. His counterpart, Lee Byung-hun is serviceable here, but doesn’t display enough emotion to show that he’s really fallen into the abyss he’s been staring at. It might have been a filmmaking choice to keep his character mostly stoic throughout the film, but when Byung-hun finally has his emotional release it seems to come a little too late.

With a runtime of nearly two and half hours audiences should prepare themselves for an endurance test. That’s not to say the film drags at any point – every scene is relevant and reveals more about the characters or pushes the plot along – but audiences will be inwardly wishing that Soo-hyun would just get his ultimate revenge over with as the film nears its completion. With that said, the ending is sure to disappoint some in the audience in that Kyung-chul’s punishment doesn’t quite match his crime.

I Saw the Devil is relentlessly stimulating and may unfairly be lumped together with the other well-done violent thrillers to come from Korea. It differentiates itself, however, by being a film to be experienced as well as watched. Revenge is a subject that speaks to everyone on a very personal level. No one can know exactly how far they would go to settle an unimaginable grievance. While Kyung-chul may be the titular character, the devil viewers see may be their own.