I Saw The Devil might be the kind of film you desperately want to recommend to others, but find yourself wondering what they will think of you afterwards.

The film provides a visceral rush of almost perverse pleasure and it is utterly unabating in this nature. As a result, it will not be a film for everyone. The violence may start to seem ‘unnecessary’ for some and its nasty nature may colour your impression of its overall enjoyment. You will all be squirming, your appetite for such squirms will make the difference.

Its divisive nature makes it an interest piece of work regardless of which side you find yourself on though. It can never be accused of being dull or pedestrian.

As for the cast, it places two of modern Korean cinema’s finest actors – Lee Byung-hun (Joint Security Area, A Bittersweet Life); and Choi Min-sik (Shiri, Oldboy) – alongside one its best directors in Kim Jee-woon.

School-bus driver Jang Kyung-chul (Choi) encounters a pregnant woman named Joo-yun. He knocks her unconscious, later executing her at his home and dumping her body parts in a local stream.

The police eventually find the body parts, including Chief Jang, Joo-yun’s devastated father and Kim Soo-hyun (Lee), her fiancé and an agent of the National Intelligence Service. Kim swears revenge and the hunt begins.

However, the film subverts the traditional revenge thriller formula, one so popular in Korea, where a long quest to find the attacker ensues. Instead, Kim manages to uncover Jang as the killer and soon finds him. But a quick revenge will not do as the agent enacts a longer-term plan to square the scores.

There is a repetitive nature to how people seek revenge and the lack of fulfillment that many revenge-seekers feel. The vicious circle of attempting to gain redemption through vengeance is what brings Kim back to Jang over and over again.

For the audience, this means revisiting violent confrontations and being subjected to the blood-stained battles between the two, and then a further cannibal friend of Jang for good measure.

The film also unpacks the impact living such violent lives has on the characters, meaning the battle between the pair is as psychological as it is physical. A concept anchored throughout by the quote from German philosopher Friedrich Nietzsche: “He who fights with monsters should be careful lest he thereby become a monster.”

While it is not predominantly a horror – though it borrows many elements from the genre – there is a frightening vein throughout. Combined with the constant violence and a runtime well over two hours, it creates a challenging watch.

In some senses, I Saw The Devil is an exploitation movie which has instead recruited the best director and cast possible to produce something equally violence and confronted, but stylishly crafted and performed. A shock and awe project, it is not for everyone, but for those who can handle shocks they will adore the awes.