Although this is not horror, I saw this film during a horror festival. Their idea was to introduce "horror" that was more related to crime/violence, rather than real horror. Was it a success? Yes. I usually lack words to describe what I like about films, especially when I really like them. I wanted this film to be good but I thought it would end up being a normal film - I was wrong. The acting was really good (from main to secondary characters), the crudeness of a life of crime was very clear, the confusion of the main character when facing a clarity that wasn't there before was heartbreaking and your heart will shrink and shrink an shrink as the story goes on. This is not a pretty story and it's not embellished. This is about a girl who was brought to a life of crime, dealing with lack of love and working to survive. It's a film about a human being that is trying to find her spot in this world of horror - horror done simply by people who are just evil.
As a last note, I would also like to add, since this is a Korean film, I was worried my friends wouldn't enjoy it (since a lot of times cultural differences are plastered in the films but unless you understand those differences you won't be truly able to appreciate the work before you), but they actually did. If you want to introduce yourself to Korean films (and if you like action and violence), this is a really good film. If you know something about Korean culture it won't hurt, but if you don't you won't find yourself lost in translation. Totally recommend watching this.