Not for the squeamish, but the number of twists, imaginative uses of vampire mythology, gorgeous visual extremes, together with interesting and quirky characters make this one of the most stunning horror films I've ever seen. It descends into utter madness along with characters, but never seems exploitative or horrific without purpose. There are copious amounts of bloodletting accompanied by some nasty sucking and squishing sounds, but also subtle moments where you laugh out loud.
As he tends to do, Chan-wook Park keeps you off center with leaps in time and plot and situation that you have to fill for yourself forcing your involvement. And the acting is superb. Ok-vin Kim, the gorgeous actress in the difficult lead role, at 22 shows a range that leaps (and there's a lot of leaping) from impish to sexy to helpless to demonic that is remarkable. This is a really smooth, convincing, and nervy performance.
If you love the real art of horror, or are a fan of Oldboy - don't wait for the video, see it immediately.