Secrets of this film
There is so much more to this movie than most people seem to realize (judging from what I have read online, and from critics). This is because the movie mimics in form its very subject, all too well: It is indeed a film about the art of keeping up appearances. And the film itself keeps up appearances so adeptly that it is nearly impossible to see through them.
However, those with a little knowledge and patience will begin to see the hints of secrets contained within. Once this happens, the art of the film is so much better understood. It is not in fact as shallow and meaningless as some perceive it to be; it is actually quite clever.
To give away these hints is to 'bruise the fruit'-- spoil it, in a way. So I will only say a few things here: read some of the Vietnamese text which appears here and there in inconspicuous places in the film (get a dictionary); learn a couple things about Viet culture (for one, the Uber-importance of using correct hierarchal pronouns); listen to the lyrics of the English-language songs; pay close attention to the dialogue, and contradictions contained therein; and pay attention to the juxtaposition of sound and image; and pay attention to some of the parts of the film that seem the most 'low-profile.' Here the film tricks us into looking casually, even carelessly, when we ought to look hardest of all.
In interviews, the director Tran Anh Hung, maddeningly, never gives away any of the hints that he placed so cleverly throughout the film, thereby sabotaging the critical reception of his own film, but preserving the artistic aim and integrity of it. There are a couple grossly obvious hints on the official website which in a way I wish were not. Once a viewer observes that these secrets really are there, it cannot be denied that it was intentional, and artful.