The film that Samantha watches on TV whilst babysitting is George A. Romero's Night of the Living Dead (1968), a film in the public domain so the filmmakers didn't have to pay rights to use it.
Shot on 16mm film (very popular in the '80s) to give it a retro stylistic look.
Promotionally released on VHS in a clamshell box. The last major motion picture released in that format was A History of Violence (2005).
Deliberately shot in the same kind of style and using similar techniques as the splatter films of the '70s and the '80s which it emulates.
Shot over a period of only 18 days.