This movie show to us the begging of the attempt to rebuild Japan after the second world war–and did it very well. Emperor also has a sentimental side that creates an amazing reflexion of what is war and how horrific it really is.
I loved this movie quite a lot because it's not like those 'americanized' movies, it shows up the real facts of the american attempt to rebuild Japan–shows the mentality of japanese people and a bit of its culture.
Above all, this is a movie to understand what happend after Hiroshima e Nagasaki.
For the fans of the tv show 'Lost', I think there are some referencies to it. The actor Matthew Fox who was on Lost tv show is the protagonist of this movie, so if my guess is right, there are some referencies to the final Lost' scenes with Matthew Fox in Emperor.