First, Arthur’s ‘kick’ in the hotel elevator by basically forming gravity was awesome. I have to say that.
Second, Michael Caine as the father-in-law is just plain weird. And kind of funny – like, “Mal didn’t have a British accent, how is Michael Caine her father?” And why is he in Paris? And if he’s in Paris, why doesn’t Ellen Page – his student – have a French accent? Confusing.
So here’s what I’m making of the ending:
The ending leaves you wondering if the totem – Cobb’s (and, previously Mal’s, I assume) top falls (meaning he’s in the real world) or continues to spin (which would connote that he’s dreaming).
In the final sequence, as Cobb is leaving the airport, with the rest of the gang giving him the “you da man” nod, look at the other people’s eyes. As Cobb explained to Ariadne early on in the film, when Ariadne is being scouted as the new Architect for the team, the other people – the projections of the dreamer’s subconscious – will confront the others who share the dream as an intruder, like white blood cells to an infection; they would begin to stare – and eventually fight – the others. Notice that the other people – who, in a dream state, would be projections – looked in scattered directions, for their own loved ones, not the crew. This pretty much confirms that Cobb is back in the real world, in his conscience.
Now, let’s return to the absolute ending. Cobb leaves the top after seeing his children, specifically their faces; by this point, Cobb doesn’t give a damn if he’s in the real world or not. (Though the fact that he was never able to see their faces – at least as far as we know – in the 4th level (where he was looking for Fischer, and eventually Saito) kinda re-confirms that he’s in the real world now.) The top begins to wobble, and then cut to black.
But just the fact that the top’s wobbling shows it’s going to fall. Go back to the scene where Cobb is describing for Ariadne how he performed inception on Mal, implanting the thought in her mind that, when she awoke, she would remain in a dream. The top, as Cobb returns it, is still spinning when he closes the door of the safe in the doll-house. Further, in the in medias res scene of that 4th level (or perhaps it’s limbo) with an old Saito further shows this phenomenon – it continues to spin, for more than fifteen seconds at least, showing that it was not the real world. The fact that the top even begins to wobble after such a short period of time shows that it’s going to fall, and thus he’s in the real world.
Now, the one mite of logic that Nolan messed up – or possibly, in this bundle of worlds, forgot about – is one I hadn’t even figured out until my friend Kelly and I discussed it: the assumption that the plane did not cause any disturbance in the first dream sequence. This could be explained by the fact that, as you go down in dream levels, the disturbances are much more subtle, and thus disturbances on the top level would not cause disturbances as you went further down. But that’s a dubious assumption at best.
Finally, it’s a shame that Nolan didn’t try and do any plot twists of Saito trying to sabotage things, having his own inside man, the flight attendant being a Fischer double-agent, &c.
So that’s my take on Inception. You can believe my theories, or you could believe Damon Lindelof’s. Or you could just believe that whatever went wrong, it was Michael Caine’s fault. Your choice.