There’s a lot to be said about how difficult it was to shoot this film. A lot of it was on location, so they had extreme weather and the environmental conditions to contend with. Adding to that, was the fact that it was all shot in order.

According to director Alejandro G. Iñárritu, he did it this way to allow the story to grow and evolve. For him, he wanted to invest in the emotional effects of the film, and felt that the actors and the story worked better if everything was chronological.