The Tree of Life is an odyssey. It's a low budget epic masterpiece. Maybe not low budget (32 Mil.), but epic masterpiece still fits. Brad Pitt delivers a great performance as a tough luck dad, and newcomer Chastain also delivers.
There are themes in the movie that make it feel like a religious Hallmark movie, but it should feel like so. The movie is religious, from quoting the bible to asking mystifying questions about God. In fact, it goes so far that you could even call the movie "A prayer".
Part of the movie has a "yin-yang" feel. As Chastain narrates, there's two ways through life: the way of Nature and the way of Grace. Nature only wants to please itself, and Grace wants to please others. In the end, the two paths need each other.
The first hour of the movie is what I call "The Nature Part". As earlier described by Chastain, Nature wants others to please it, to make benefit for itself. Throughout the part, there's the divisive "Beginning of Earth" sequence. Toward the end of the scene, there's the dinosaur head stomp. To me, it represents the climax of the part: Grace gives in to Nature, so it could be pleased.
The next hour and a half is a dizzying epic. This is what I call "The Grace Part". There are lovely scenes with no dialouge, instead just classical music. The main focus now is Mr. and Mrs. O’brien, played by Pitt and Chastain, respectively. Pitt's performance, as Mr. O'brien is the current embodiment of Nature, and Chastain is Grace. Together the family works, not always in harmony. They are almost like the two dinosaurs, except Pitt and Chastain look much better than their respective dinosaur representations. The kids are pressured by the Senior O’brien, who needs his kids to be perfect in his eyes. The Misses instead lets them be their own embodiment, and her action pleases others. Sequence play out, and the kids are challenged by their parents to choose a side. Toward the end of the part, Mr. O'brien consults the oldest son. He tells him he's sorry for how he treated him. Maybe he also becomes Grace. The opinion is open-ended, for the scene cuts to present day, with Jack, the oldest son, contemplating the end of his brother's life.
If the two paths (nature and grace), created harmony, and Mr. O'brien also became Grace, did that create an imbalance? We may never know the path life takes to affect others, but in the end, the imbalances may create a perfect harmony: a path for life.