The film is adapted from a legend fiction of mid Tang Dynasty, when such mystical novels started to flourish in China as incipient stage from which subsequent novels of martial arts derived.

Nie Yinniang is a well-trained assassin, killing people for political reasons.  In original novel, she is illustrated as a relentless killer with kind of extraterrestrial power, but in the movie she is just a human, a skillful woman fighter having human touch and emotion.  Although it is not shot as that symbolically as I thought, still it's a film par excellence to me.  I guess the film is worth your while to watch it in theater or later online.  But if you do, you'd better get to know the story beforehand; otherwise, you will be probably like my wife who felt drowsy not long after the movie began, and in the middle of the show, she fell asleep. 

P.S. Report said when Mr. Hou Xiaoxian, the director of the film, was asked if he minded the film was categorized as a production from China's Mainland, instead of Taiwan, in Cannes film festival, he answered with a little grudge that he don't care much as long as his picture could have a boxoffice success in Mainland China.  He is right.  The picture has gained a sensation in Mainland, while only a lukewarm support in Taiwan.