This film is nothing like I expected, I'd almost call it brilliant in a way. The main character is totally great, you find her believable and are hoping she'll win against the odds. The villain is totally evil, crazy psycho but you also want him to win against his foes as well. Combining these elements makes you feel confused on who to cheer for! What's unique is this guys not just some crazy killer, there's a reason he's so screwed up and you learn more about his family throughout the film, as well as the girls. I think this is a masterpiece of crazy madness with insights into what makes someone that way. A very worthwhile movie to watch for sure.

A couple awkward parts here and there, but still, a tense and brutal movie!

I first saw Kim Go-Eun in "Memories of the Sword" (which I plan to watch again sometime; I don't think I paid enough attention to it last time),and now, this creepy thriller "Monster". And after this film, I simply must say: I ADORE her acting soooooooooooooooooooo much!!!! She commits to the role incredibly well, occasionally making me laugh, as well as making me cringe and whisper "oooo", or "eeek", or "woah", during an intense scene, or if she does something totally unexpected! After seeing Memories of the Sword again, I'll be able to compare both roles she played, while also preparing to check out some other performances of hers. But after today, I think I may personally like her performance in this brutal shocking thriller the best!! No lies here!

Definitely a sick and twisted villain too! Nice job to that actor's work as well!

There's something about the energy, emotion, humor and honesty about Korean cinema of the last twenty years that I find completely engrossing.

I had no idea that this was a Korean movie when I was first watching it on Netflix, but the earthiness and directness of the characters made it clear that it could not be from any other Asian country other than South Korea.

Almost none of these movies depend on special effects or CGI; they just depend on great casting, acting, directing, writing and action. Of course, there are some Korean duds, but the vast majority of these films succeed because they don't depend on ridiculous gun fights, which only serve to take you out of the picture. They also don't depend on unrealistic martial arts scenes, which also remove you from the story. The directors strive for entertaining realism, which seems to be lacking in almost all of today's cinema. The characters in this film are not the genius detective, the all-knowing child, or the master criminal. They are a mentally challenged woman, an abandoned child, a psychotic killer, and a bunch of greedy criminals. Don't waste your time analyzing every aspect of the film, just enjoy it for what it is.