I'd rather not rate Lars von Trier's latest movie after just one viewing because it left me with all kinds of mixed emotions, but I'll give it a shot anyway.
Since "Melancholia" opens with a stunning 8-minute slow-motion sequence that leaves no doubt whether the end of the world is upon us or not - and afterwards still goes on for another two hours - I'd say it's some sort of "Anti-Armageddon". Admittedly, it's rather hard to enjoy a movie that explores depression, anxiety, fatalism and nihilism as its main themes and von Trier clearly brought some very personal insights to the table, dealing with depression himself for a couple of years now.
While the whole cast deserves some praise, Kirsten Dunst manages to stand out with what many consider (myself included) the best performance of her career. Charlotte Gainsbourg is a very strong second female lead and "Melancholia" ultimately comes down two the story of those two sisters and their emotional journeys in the face of impending doom.
As soon as the screen turned black and the credits silently began to roll, I started trying to figure out what to make of this movie. I decided to give it such a high rating because it managed to get in my head and stick with me throughout the following day (I spent most of my time on the IMDb board and several other movie sites today...) which is usually a good thing. I advise you to consider this review a work in progress, though.