A blatant triumph of style over substance ... unfortunately even the "style" is already looking a bit weak as it's mostly 2003 CG graphics. The movie is based on a 35 episode Anime TV series. Movies based on Anime series or Manga tend to A) assume you already know the mythology, and B) try to compress nearly all the content - without trimming - into a two hour package. This movie certainly suffers from both these problems. All kinds of weird and non-sensical things happen, but my personal favourite is the four neo-humans arriving at an abandoned castle - where they find an utterly massive robot army available for them to turn against their enemies. No explanation of that is ever given, it just is. The movie presents as science fiction, but it also has ghosts and multiple unexplained (and pivotal) alchemical happenings.
It seemed fairly clear that it was an anti-war statement, while duly noting that it's very hard to break the cycle of hatred and revenge killing. But it's long and makes no damn sense and no longer looks very good because CG has advanced so much in the past 15 years.