I think it is sort of a misconception to say that this film is about the beauty of life, and nostalgia for the past. Through the narration and the titles, ambiguity is introduced into the mix. Mekas remarks multiple times the fact that this images are to an extent unreal: people are not so innocent as these images show them to be, people do not love each other as much, other people's perceptions of the same events are quite different, and he isn't just filming his children but he is inventing his own childhood through them. "This is a political film", says the movie repeatedly, and yet in the artificial idealized world of the film politics is entirely absent -there's no poverty, no war, no questioning of his bourgeois lifestyle-, and that's precisely the point: to show not how the world is, but how we want it to be, and how that desire can sometimes become a shallow fantasy. We long for paradise, but paradise is lost. We can only get glimpses of it, not in everyday life, but through it, beyond it, inside us.
My complain with the movie is a matter of form. I just don't like the accelerated frame rate, the fast cuts, the repetition, the inflated length, the out of tune music. I sort of enjoyed it for the first hour and a half, but after that it became a blur. It had in me the effect of starting out as a beautiful experience and ending as a nightmarish reality without meaning from which I just wanted to escape; one is dying to know people's names, to hear someone's voice (besides the rather silent Mekas), and to stay in one place for a while. But then again, that feeling is also part of Mekas' scheme. Beauty comforts as by what it evokes, but hurts us by how unreachable it actually is.