An overlong, meandering tale of guilt and sacrifice. I think the story itself could have been told with more power via a linear, compact story-line, but this unusual technique does manage to distract from some of the larger plot-holes. Will Smith's emotional distance also moves us away from sentimentality - one scene near the beginning works well to confuse us as to his true character. The air of mystery is intriguing, but I doubt it work on a second viewing. Rosario Dawson was great, providing all the heart, while Barry Pepper and Woody Harrelson are underused.
In the end, it all feels a bit empty - it's hard to understand our odd, emotionless protagonist, much less his motivations for what he does. The Christological theme was interesting, but given where the film ends up, unnecessary and incorrect. The whole film is rather pretentious, in retrospect.