J.K. Simmons never says one word during the entire movie.
Samuel Beckett's classic one-act play "Krapp's Last Tape," first performed on October 28, 1958, has a similar premise and probably was an inspiration for the screenplay.
Cinematographer Pete Villani said in a Q&A that each era was shot on different lenses to better distinguish between them.
J.K. Simmons and Harold Perrineau previously starred in the HBO series Oz (1997) which writer-director Michelle Schumacher appeared in as wall.
Sebastian Stan played a character named "Steve" in this film. In the Marvel Cinematic Universe, he played Bucky Barnes, the best friend of Steve Rogers/Captain America.