It has lots of consistent retro-modern late 1950's like design, including the music score. It has developed psychology for all characters, be them heroes, villains or secondary characters. It knows how to build upon clichés rather than blandly restate them. It has great acting and impeccable story-telling. Last but not least, what I always fall for, it has a didactic story, -- and what more, one where adults learn, too. Where ethics and esthetics join. I'm sure Ayn Rand would approve. The greatest movie I've seen in quite a long time.