Kim Jee-woon is a master with the camera. It's insane. There are so many amazing shots in this movie, weird camera tricks, just lots of fun stuff. The settings are great and Kang-ho Song is terrific as "the Weird" member of the title triumvirate. Not everything works, though, and there's way too much going on at times, but overall, it's fun.
By the way, if you love horses and think they're treated like shit in movie production, which they are, this is really not a movie for you.