I saw this movie this Sunday and it was well worth it. Probably one of the best movies ive seen, ever!
And as a lucid dreamer, i can totally relate to it. Interestingly enough, i started a thread on lucid dreaming a few months before on typc
Some replies to some posts above mine, might contain spoilers
also another thing i experienced is that the entire world..or city or place the dream takes in need not be meticulously crafted...that's why i do not get the "architect" thing...for me at least when i open a door in a lucid dream...it looks like a room...with furnishings/look based on what type of room it is(in that particular dream). Its as if we create the surrounding "on demand" and not ahead of time.
also in the movie, Cobb says to Ariadne something along the lines of
"Dont worry too much about the details, set up the big picture and people will fit it up with details"
I think so too
maybe it signifies transitions between different layers of the collective unconscious...or even going deeper and deeper within ones own conscious
I read somewhere that in real dreams, "near infinite" dream time might occur within just a few seconds of real time. So i think the inceptions time-scale...even though it grows exponentially as one traverses the layers, is still slower than actual dream time.
but its a pretty nifty idea the way they explained it in the movie