> Having to constantly track how many levels deep you are, how time flows at that level, the rules for what may/may not wake you out of a level, the specific ac

> Having to constantly track how many levels deep you are, how time flows at that level, the rules for what may/may not wake you out of a level, the specific actions going on during the specific levels at those rates of time, how they interact all together, and whether you were right about the level the movie took place at the entire time and what that means for it all, and the information you've learned and leaned on to make the assumptions you have at every point. The cool thing about the movie is that you can misunderstand nearly all of that, and when the music begins playing across all three (four?) dreams you immediately grasp the consequence for the plot. It's like not caring about Gnu make's console diarrhea flashing past the screen, until the final message tells you a test failed and suddenly going, "Oh, shit."