Just saw it. The issues raised in the film were fascinating. Regarding spirituality, belief in God, how we choose to perceive reality, what we are most comfortable with, and how many of us meaninglessly distract ourselves as part of a throng.
Uses a lot of symbolism.
The whole thing, the message, came together in the final half hour, which was very cool.
Leaving us with the question, "Which do we prefer?"
I won't say more as I don't wanna ruin it for anyone.
The way you interpret the end may say more about you and your world/spiritual view than anything objectively revealed in the plot itself. That's what I've found, from my discussions with friends. Which is itself interesting.
If you plan on seeing this movie "someday" ... I urge you to see it in 3D while it is still in theaters (if you can still find it).