There are several reviews here which provide a perfectly adequate overview of the movie as a whole, but I want to put in a plug for what is, to me, its greatest appeal. This was one of the first DVDs I ever watched, and it has the first commentary track I ever listened to.
I am a tremendous admirer of Jason Isaacs, who plays a sneering bully (Col. Mekum) in this movie. His role is quite small, but he joins Paul Anderson on the director's commentary and reveals himself to be a man of unusual intelligence and wit. Anderson and the producer, I think, get completely absorbed in self-congratulatory Fanboy minutiae, but I thought Isaacs was hysterically funny. An unusual treat for that reason.