13 The character Saito was written just for Ken Watanabe. Nolan felt that he didn’t receive enough screen time in Batman Begins and wanted to give him a larger role.
Cobb being the director of the whole thing, Arthur the producer, Ariadne the production designer as she designs the dream levels, Eames the actor as he plays the imposter of Peter Browning, Saito the studio executive for funding the whole operation, and Fischer being the audience as all the dream levels were created to convince him.
15 Joseph Gordon-Levitt went to his audition after a brief character summary, wearing a full suit “just in case”, unknowingly matching his character’s wardrobe perfectly.
16 The “Penrose stairs” (with a woman perpetually picking up papers) that Arthur shows Ariadne is a reference to a lithograph print by the Dutch graphic artist M.C. Escher.
The print is usually called “Ascending and Descending” or “The Infinite Staircase”, and was first printed in March 1960; Escher is well-known for his drawings exploring optical illusions and real architectural, mathematical, and philosophical principles rendered in fantastical ways.
17 Warner Bros. released a prequel motion comic called Inception: The Cobol Job as part of its marketing campaign for the movie.
The comic features Cobb learning dream sharing from his father-in-law and his work for Cobol Engineering with Arthur and Nash. It unfolds the backstory of what happens between him and the company and how he agrees to perform the extraction on Saito.(source)
18 Except for one, Joseph Gordon-Levitt performed all his stunts.
