After three weeks of shooting, Amy O'Neill was replaced by Jill Schoelen. Schoelen has said that she did not have much interaction with the cast since many of the scenes had already been filmed with O'Neill and in most cases just needed to make quick re-shoots with Schoelen.
While the film flopped in cinemas, it has since become a classic among horror fans, largely due to its homage to William Castle, who is known for creating theater gags such as the ones depicted in Popcorn.
The reason that the teenagers listen only to reggae music is because this film was actually shot in Jamaica.
The title "Popcorn" was linked to an element in the story. This element was removed before the final cut. The producers and distributor liked the title so it was kept anyway.
This was such a box office disappointment in the United States that in many markets it bypassed first run cinemas and was booked directly into second run/discount cinemas.