Trivia

Co-writers Mark Cantu and 'Jennifer Ayala' were the original authors of the story, which was going to be more exploitation-based than an actual crime drama. The change in tone came through when Mark Cantu began shooting the trailer as a proof-of-concept for investors.

There are several nods to other crime dramas and thrillers throughout ECHO: Darren's last name (Stensland) comes from L.A. Confidential (1997); Detective Capa (Mark Cantu) is named after Capa from Danny Boyle's Sunshine (2007); the murder scene where Darren goes to kill Vicente is an homage to the shower scene in Alfred Hitchcock's Psycho (1960); in the scene where Sorenson (Paul Scofield) is executed, the framing of the shot is meant to evoke a similar scene from Miller's Crossing (1990); and finally, the scene in which Darren drives to the warehouse to uncover the truth is a small nod to the ending of Christopher Nolan's Memento (2000).

Sorenson's body was meant to be shown in the crime scene where Vargas and Burnett are introduced; however, since there were delays with make-up f/x on the day, director Cantu decided to shoot without the body, and insert close-ups of carnage later.

Director Bryan Oritz has a brief appearance as "Detective H. West," an homage to the Jeffrey Combs' character from RE-ANIMATOR. Ortiz is another actor/writer/director from San Antonio.

Co-writer/director Mark Cantu wrote the first 70 pages of the final shooting script in roughly 4 days. Although there were several minor changes to the script in terms of dialogue, a majority of the draft is intact for the film.