Since there is a danger of revealing too much here that would spoil the film for the reader, I can only say that in the end we are left with as many questions as answers. The story demands multiple viewings, and I look forward to watching the DVD when I will be able to stop and play back scenes that I have questions about.
There is a good deal of psychological stuff going on, with great dramatic moments and lots of action including fights, shoot outs, and explosions to keep all The Dark Knight fans happy. There are certainly many times when the fate of the characters is in question, and the fact that Nolan has jammed so much into the film and yet gets the audience to care on an extremely emotional level about these characters is testimony to his craft as a filmmaker.
More importantly, the viewer will keep questioning what has happened on the many levels, waiting to confirm that the dreaming is actually over and reality has come back into play. Nolan challenges our perceptions all the way, and even in the last moment of the final scene, you will jump in your seat as your brain squirms with what you see in the last seconds, a titillating visual that makes you yearn for the rewind button.
Inception is a different kind of movie experience, involving the audience as much as a foreign film that forces the brain to work because subtitles have to be read. In essence, the viewer becomes engaged in the film and pulled into a vortex of dreams within dreams, worlds that are real as the dream thief and his team can make them. Ultimately the film succeeds because we walk away from it thinking about our own dreams and real lives, wondering how we can survive in the day-to-day real world without dipping into dreams to find the answers, but then we will question whether dreams are a respite from it all or merely another pathway that leads us to a corridor with too many doors and not enough time to try to open them all.