On the first night of shooting, the generator broke night meaning that no lights were available. As the film was shot entirely in night vision, and close up night vision not requiring light, all of the close-ups were shot on that night with the wides all being shot the next when a new generator was located.
No sound was recording during principal photography and was entirely dubbed in ADR. Some of the sound is purposefully out of sync to create a sense of displacement for the audience.
Bon Iver's "Woods" was put on repeat on a portable CD player during Evelyn's emotional speech in the woods to get actress Kayleigh Lawrence in the right mood.