This is George A. Romero's second film, and according to him, his worst. He stated that the writer was "very lazy" and showed little interest in the production, leaving halfway through the shooting.
Briefly seen just after the 54 minute mark, the clapboard for the commercial shoot reads "ROMERO."
Although Lynn (Judith Ridley) is supposed to be older than Chris (Raymond Laine), Laine was, in fact, older than Ridley by ten years.