First, the computer animation is stunning (at least to me). The characters' expressions and gestures, the landscapes, and the animals (all hybrids of known animals) are so far from the animation that I saw as a child that it seems to come from another civilization. (Maybe it does.)
Second, while the films assumes a naturalist view of the world, it undermines itself wonderfully. The Crood family begin as fear-based pre-humans (or semi-humans) whose only goal is not to die. But their teenage daughter wants more. She wants to live and be curious. By meeting a more evolved character, the Croods begin to think about "tomorrow" and end up "following the light."
It is all delightfully done, mind you--the hyper-slapstick and constant verbal and physical humor can be nearly hysterical. But it does not fit Darwinism, which allows for no transcendence of the material world. The Croods, you, see begin to act beyond instinct and conditioning. They dream; they explore; they hope. They are not merely evolved animals.
Thus, the human essence, made in God's image and likeness, shines through even this supposedly Darwinian tale, which makes it even better. This also chimes in with a New York Times article which recently related that an atheist group was holding "services" and wanted more of a sense of "transcendence."