Hard to describe this movie in a foreign language. You can read the other reviews for details, i believe that their descriptions are right. All i can say is that this movie is a strange movie, strange in a remarkable way. Kim Ki Duk has written the script, don't expect something heavy or depressing, expect a modern film noir(?) and some terrific performances from the actors. (The actor who plays the gangster gives one of the best performances i have seen recently). If you want to know some similar movies, i will not be able to help you, because, movies like this, are a genre of their own. I wonder in how many ways, Hollywood would destroy Kim Ki Duk's script: Τhis is not a comedy, this is not a gangster film, this is not a drama nor an action film, but it manages to combine all these and make something new. I am looking forward to watch his new movie, Pieta.
PS I haven't mentioned the director and this is not fair because he also did a great work.For sure,i will search for his other movies.