Trivia: John's request for "guns...lots of guns" mirrors a line Keanu Reeves has in The Matrix.
Trivia: The scene in which John pieces together a custom revolver using parts from various 19th century guns is a reference to the classic western "The Good, the Bad and the Ugly." There's a scene in that film where the character Tuco does the exact same thing in a gun shop.
Trivia: Somewhat ironically, the actor who plays "The Elder," the man who sits above the high table, is younger than most of the other actors in the film. He's about 10 years younger than Keanu Reeves, Laurence Fishburne and Jerome Flynn, about twenty years younger than Anjelica Huston and about thirty years younger than Ian McShane.
Trivia: John Wick's fights while ascending the Continental in New York are reminiscent of Bruce Lee's Game of Death, where he too had to fight varied opponents as he approached the showdown.
Trivia: Halle Berry broke three ribs whilst rehearsing her fight scenes with Keanu Reeves.