I've been watching more of the films out of South Korea lately, and have largely been impressed by the skill -- in acting, directing, and special effects -- that is apparent in many of the titles. This one is certainly no exception.
Having said that, I can't really speak to the historical accuracy of it. The central female character, the Queen, definitely existed and the film does seem to follow the rough details of how she influenced Korean history, but my impression is that some finer details may have been sacrificed in order to produce a more compelling film.
The filmography is beautiful, a blend of beautiful nature shots that make you feel like you're in the Korean countryside, quiet court scenes and almost Matrix-esque swordfight scenes that still flow together seamlessly.
The only difficulties I had with this movie were that, as with most subtitled films, sometimes it's difficult to follow exactly who the various characters are and the subtler nuances of what they are saying.
Overall a very well-done film that is well worth the 2 hours spent watching it.
