I watched this too, and I'm astonished that it was totally NOT intellectual or difficult to understand. I didn't even notice any pretense of it either.
I actually liked it a lot, but it was just a heist movie with a gimmick. Watching this flick made me lose a lot of faith in humanity - I keep hearing from people that they didn't understand it, or that it was hard to follow. It wasn't. It was hella straightforward and everything was chewed up and fed to the audience. "You have to really pay attention", yeah, only because a lot of things happen. Not because these things are difficult to understand.
If you didn't understand it, I'm sorry, but you must have ADD or something, or you're just stupid.