Plenty of research goes into the development of a film. But during the production of Return of the Fly, some of the best advice was given by fans who loved the film.

Serving as the sequel to the 1958 film, The Fly, Return of the Fly retained several plot devices that captivated audiences in the original film.

A transporter machine is used in both films, though the device has seemingly been refined between the original and the sequel. According to Return of the Fly’s producer, Bernard Glasser, those involved in the film were able to take some helpful tips from more than a few fans to help develop their film.

“We were able to improve the original transference machine used in The Fly,” said Glasser during an interview with The Register. “The studio received literally thousands of letters from science fiction fans following the release of the first picture. Quite a few suggestions received from these enthusiastic fans proved scientifically valid upon analysis, and we adapted our new transference machine to meet these stricter and more plausible specifications.”

The special effects, props, and costuming were also improved upon. “The Fly mask is entirely accurate,” said Glasser. “It’s a scale model of a microscopic photograph. We feel, though, that our new head has more horror impact than the one used in The Fly. It’s bigger and like a real fly’s head; it will pivot on a 360-degree axis.”