There is a promise early on in Life of Pi that "this is a story that will make you believe in God", which is a big claim. Its addressed from Pi to the author Yann Martell, to whom he is telling his story of survival adrift on the Pacific Ocean, and like a lot of the film it's not quite saying what it means. This is a film that everyone involved clearly realised had to be about "stuff", and the subtext and imagery fly thick and fast around it, especially once Pi is shipwreck, adrift with only a tiger for company, and starting his odyssey across the sea.
The is a movie about stories, and the power of those stories, in the sense that the power they have over you is something you choose to allow them to have. When challenged on the truth of his tale, Pi gives a second version, darker, more mundane, but equally able to explain the outcomes at hand. He challenges Martell (and by extension, the audience) to choose which version to believe - which story is true, or rather, which one do you want to be true? With no other guidance, it is implied this is an ink-blot test for the soul, and so it goes with God. Interesting point.
Outside of the philosophising, Life of Pi is a well made, slickly entertaining movie by turns funny and dramatic. It takes a long time to get to the pivotal shipwreck, filling in Pi and his life to date, before setting him on a doomed freighter, and the sinking itself is a gripping set-piece, the ship sent below by the crushing power of an angry ocean. From then on, Pi and Richard Parker, a Bengal Tiger, try to find their own balance and survive drifting to wherever the currents take them. The tiger himself is a striking piece of animation, and at times it was a joy just to watch him stalk around the lifeboat.
It also worth mentioning that the film is staggeringly well shot; obviously shot for 3D but even on a TV screen the depth of field and brilliance of colour makes it one of the best looking films I think I've ever seen. It leads to sense of scale, and isolation, that works in the films favour and whilst its not the fastest paced thing ever, the lyrical composition works well.
In the final analysis, Life of Pi is a very well made, thoughtful adaptation. I'm not sure it made me believe in God, I'm not sure its depth is that great, to be honest, and stories about stories are reasonably common. But it's the imagery that lingers on after the film, that sense of wonder and loneliness, that I think will live on beyond its running time.