"2046" is the number of an apartment where a journalist lives. It is also the title of his novel, which takes place in the future. And it is also the last year before the 50-year period the Chinese Government promised to let Hong Kong remain as it is...
Wong-Kar-Wai comes back 4 years after "In the mood for love" with another refined and delicate movie, although this one has not the same strength as the previous... Because the director wants to develop too many themes (love, the power of memories, the lack of communication, the importance of living now...). "In the mood for love" was maybe more focused on a love story and the impossibility of living it. "2046" is a sort of sequel, but we don't understand very well where the director wants to lead us.
Apart from that, the film deserves to be watched because it is original, it explains that we don't have to live the future in putting there the hopes which belonged to the past, otherwise life has a wasted meaning. The film is colourful and cinematography is excellent. Very slow, yes, but a film like this one follow its own poetry, images here are much more important than words.