About 200 extras appear in the party scene that opens the film. They were recruited about two days before shooting, partially through the help of local club and radio DJs in Montreal. They worked for two nights in freezing weather; director Renny Harlin states on the DVD commentary track that he was bowled over by how cooperative and enthusiastic they were, despite the uncomfortable conditions.
According to the DVD commentary, the filming of the beach party took place in December. The original location was flooded shortly before the scene was shot, and the scene had to be rescheduled at a new location at the last minute. The location that ended up in the film was a sand quarry.
Caleb's last name is Danvers. Danvers is the name of a city in northeastern Massachusetts, only ten miles from Ipswich, where this movie is set. Danvers is also the modern name of "Salem Village," the real center of the so-called Salem witch hysteria of 1692-93, which also included Ipswich.
In the last scene when Caleb raises his hand to mend the windscreen, just as the windscreen is mended near his raised hand, his hand rises again from the bottom displaying the 'millisecond' overlapping mistake of the film editor.
Chase tells Pogue and Caleb that he heard they were swimmers while the pair are playing foosball at Nicky's, but his mouth doesn't quite match up to the words, almost as if he's yelling it and then it was voiced over.