Many of the props for the film were customized to fit a metaphorical or symbolic message. At the heart of the film is a connection to Edgar Allan Poe's "The Raven". The character of Alan Wright is a reflection of the titular "raven," and his dog tags share the birth date of Poe himself.
A lot of the windows in the film were the key source of light. Because of this, the cast and crew had to work fast with each scene to maintain the same light throughout that shot. The idea to do this was a tribute to the styling of Director Terrence Malick and DP Emmanuel Lubezki.
The movie was originally written to take place in modern day, with the main conflict being the war in Afghanistan. When appropriating the budget, the decision to adapt the story to a period piece actually saved the production money, contrary to the norm.