if you think that reflecting deeply on the movie Inception requires some serious brain gymnastics, just consider what it was like to star in it; Leonardo DiCaprio explains that shooting the film was both a mental and physical challenge:
Nolan, a stickler for naturalism, insisted that his actors and crew bring his vision to life without the use of computer-generated effects as much as possible, from making Joseph Gordon-Levitt perform zero gravity fisticuffs inside elaborate, rotating sets to asking the cast to feign peaceful slumber inside a van during a high-speed chase. “Actually, the van sequences were much easier than doing five pages of dialogue and the whole set is tilting and we have to hold onto a bar in order to not slide off the stage.” DiCaprio said. Source
Gordon-Levitt’s fight scene in the rotating hotel