There's some exceptional visual trickery present in Bad Guy - Kim Ki-Duk's play at duality and reflection with constant graphic references to glass and mirrors, though obvious, yields some great-looking results - but unfortunately the metaphor just doesn't sustain Bad Guy. It's an interesting byproduct of a film that preoccupies itself more with repetitive scenes of violence or threatened violence, which starts out menacing but falls victim to diminishing returns until you've basically tuned all the sound and fury out. Worse yet are the utterly bland main characters, a hopeless and unsympathetic brat-cum-prostitute and the progenitor of Kim's archetypal but unpolished silent man of action. Like the film, these characters and their respective performances are competent, but completely lacking in dramatic inflection. You spend nearly the entire movie waiting for it to break the cycle of total sameness, but by the time it finally does you're beyond caring.
Totally skippable. It doesn't even have the distinction of being significant chronologically for Kim - The Isle came first and is, by all accounts, better. It's good that he went on to make much more provocative, fleshed-out films than this. I guess it served as a stepping stone for him.