Great movie overall, although I do have to agree with those that say it's a bit overloaded with exposition (it seems like all anybody ever does is explain the "rules" to each other), and perhaps more complicated than it really needed to be. And the final act did get a bit too chaotic and hard to follow (at least on first viewing).
But just for the ingenuity and brilliance of the concept, and for the fact I was absolutely RIVETED to the screen the whole time, I'd still have to give this an excellent. There was something almost hypnotic
about the whole experience, as if you were falling deeper and deeper into a dream yourself right along with the characters. I love that.