The second thing that was somewhat surprising to me was the largely linear nature of the narrative. Being a fan of Terrence Malick, I was prepared for some unconventional storytelling; he never really has played by the rules. Reading many reviews, though, I was expecting something even more experimental than his usual fare. Strangely, I felt the film played out in an intelligible, sequential order and it was not quite as elliptical or obtuse as I had been lead to believe that it was. Many reviewers seemed to understand the film primarily as an impressionistic flood of images, sounds and existential questions on family, nature and spirituality, and only that. If the film is understood as a dialogue between the main character -- the oldest child in the family, played as an adult by Sean Penn -- and God, the narrative becomes quite coherent and linear. Penn's character asks questions and God answers them. Within those questions and answers are explorations of nature and Grace, love and loss, memory and experience, childhood and maturity, faith and family, but all of it is enfolded into a call-and-response interaction between God and humanity.
Another surprise is that the character development -- mostly that of Pitt and Penn's characters -- is substantial and deeply affecting, though it is a particularly Malickian treatment of character. Even as the characters sometimes double as ciphers for some larger concern, they remain recognizable human beings, as real and alive as any that I've seen on the screen in quite some time.
The last thing that surprised me about the film is the explicitly Christian themes, imagery, language and metaphysics that run throughout, which I've already hinted at. These aren't subtle undertones, mind you, but extremely overt and inherent in the fabric of the story, which was a delightful surprise. The film opens with a verse from Job: "Where were you when I laid the foundations of the Earth?", and it lays the foundation (so to speak) for much that we will end up seeing in more ways than one. As I've already stated the narrative is moved along by voiceovers of various characters asking questions of God. Some of the questions are 'unanswered', others end up very much answered. But the dialogue with God plays a very central role in driving all of the action.
In response to one such question from a character, the creation of the universe ex nihilo is shown. Later The Fall of man is depicted analogically in a sequence where the main character finds himself rebelling and sinning, and not understanding what has taken hold of him. Resurrection is also hinted at in a couple sequences. In one scene a pastor is giving a sermon on Job, and as the eldest son listens he wonders "is nothing in this world deathless?", as the camera pans up to a stain-glass image of Christ. Later in the film there are eschatological depictions of resurrections of the human dead, though if you blink you might miss them. To add another dimension to all this, there are also hymns that comprise some parts of the score, the film closing with a choral chant of "Amen".
I've somewhat exhausted the topic of things that surprised me about the film, so let me comment on a few other aspects that require it, and then be done.
Malick's eye for detail is phenomenal. The cinematography is exquisite, every frame seems delicately crafted, and the subjects for his lens are no less extraordinary; from the microcosmic to macrocosmic, and back our familiar world of "medium-sized objects". Even if the film had nothing of interest to say (which is emphatically not the case), the craft of the film is a wonder in itself. Stunning, sensational cinema. If Lubezki doesn't win the Oscar for cinematography than there will have been an injustice done.
Though, the details Malick has such a knack for isolating aren't only aesthetic. The subtle character moments and interactions contain a greater depth and are more relatable than most standard drama fare. The specifics of Malick's world are often kept from being nailed-down to any immediate context (though within the context of the film they are precisely positioned), and thus are free to become more universal in scope. So despite the obviously highly personal nature of the material -- many of the details of the film mirror details from Malick's own childhood -- it never feels like it's an internalized contemplation, with contours of story only accessible to himself, but rather a gift for all to participate in, open enough to be universal but specific and localized enough to be real.
I imagine I'll write many more words on this film in the future as my sense is that it is infinitely inexhaustible film, but these are my immediate reactions. The Tree of Life is an ode to all of Creation, the creatures that inhabit it and He that calls us forth from nothing to participate in it.