Faethor Ferenczy’s review published on Letterboxd:
I Saw the Devil, Kim Jee-Woons last Korean movie before his not quite so successful attempt at Hollywood with The Last Stand.This gritty uncompromising revenge flick exceeded all my expectations for it. When a pregnant girl, the fiancee of a detective (Byung-hun Lee), becomes the latest victim of a serial killer (Min-sik Choi), the grieving detective makes a promise - to find the killer and inflict 10000 times more pain upon him, than the killer gave to his dead fiancee. He becomes single minded in his quest, revenge is all that matters.
This is a very dark, very violent and gruesome movie. At the same time it's directed masterfully with some great visual flair and delightful cinematography. The oxymoron 'beautifully ugly' applies here. I liked the concept of this movie and I was hooked until the end. It was a film where the detective became so single minded and ultra focussed in his mission for revenge, he lost sight of anything else including how his actions may affect other people. His brutal punishments for the killer brought equally brutal punishments to those he cared about. He may have achieved what he set out to do, but at what cost? It was a movie that stirred up mixed emotions because you could sympathise in his quest and as a viewer I also wanted to see him inflict pain upon the murderer of his girlfriend, but at the same time I could see what he could not. I could see the repercussions beginning to happen, I could see how his sense of right and wrong were being warped, and I could see how his quest for revenge was turning him almost as sociopathic in behaviour as the person he was hunting. Plenty of food for thought.
Of course, there were some faults in the script, and at times some suspension of disbelief is in order - but I'm willing to overlook that due to the strength of the overall message of the film. The raw emotion it deals with is more important than the finer plot details. The acting by both Byung-hun Lee and Min-sik Choi is great and really drives the film forward with intense visceral performances from both. Min-sik Choi comes across as a slimy dispicable evil character and I really did want him to die horribly. Byung-hun Lee successfully shows us a character that has suppressed all other emotions, leaving only a single minded burning desire for revenge. One other thing to mention before finishing off - the violence and torture scenes in this movie were extremely well done and looked so realistic and brutal, it was hard not to look away. I understand people who don't like gratuitous violence and gore in movies but in this case I feel it was all warranted and only emphasised and added to the overall emotionally raw and brutal tone.
In summary - A masterfully directed, visually fantastic, mentally deranged, visceral, stylish revenge flick that actually makes us think twice about revenge. 9/10