Why was everyone in this movie so sure that Fischer would act on a thought that first occurred to him in his sleep? I'd put the probability of that happening at well below 50%. He could forget about his decision immediately after waking up or he could simply dismiss it later, the way most people dismiss all the variegated nonsense they dream about. Isn't sleep one of the worst possible states for implanting ideas into people anyway? I still have a pretty good grasp of the Communist ideology which my teachers endeavored to implant in me at school in the 1980s, but I honestly don't remember what I dreamt about last night.
Inception reminded me once again of how atypical nerdy instincts about everything are. Every nerd who's ever lived would find Ellen Page far superior to Marion Cotillard, yet in this movie the protagonist is made to obsess endlessly about Ms. Cotillard while ignoring the Ellen Page character as much as possible. From the point of view of the plot Ellen Page's lines might as well have been delivered by Michael Caine because except for a brief, inconsequential moment no one in this movie seemed to even notice that she was female.
Also, Cotillard's character was named Mal. There would have been nothing wrong with this in a novel, but since this was in fact a movie, I misheard Mal as "mom" several times, partly because the name first popped up in a conversation between DiCaprio and his screen father. I'm sure I wasn't alone in thinking that in that scene they were talking about Leo's screen mom. The plot was confusing enough already, so adding to the potential for confusion by giving characters ambiguously-sounding names was a sloppy move.
Anyway, these are all minor quibbles. Overall it's a pretty remarkable movie.