3-4. It is so brilliant in its more high-minded respects, its delivery, its deep thought, its varied complementary metaphor, that the simplicity of its characters and conflict are really unfortunate. It's impossible to ignore, on multiple viewings, the lack of humanizing emotion present here. And that's really a shame, given the abject beauty of the film's spiritual philosophy.
I haven't seen an anime like this before and hope there are more out there that are as dark and carefully crafted in theme. Excellent and hypnotic use of sound. My only crit is that the religious references were made quite aggressively at times, which may have detracted from (what I thought was) the film's central message -- but I haven't read the book yet; maybe it was supposed to be like that?