There were three characters that were supposed to be displays in the Waxwork, but left out of the film for legal reasons: Jason Voorhees from the Friday the 13th series, five children from Village of the Damned (1960), and The Thing (1982).
Galligan hated that Hickox made him tuck his shirt in for the scene where his character leads the police into the wax museum. He recalls catching the movie on USA's Up All Night once and hearing host Gilbert Gottfried say "We'll be right back with Waxwork starring Zach Galligan after forty cheeseburgers."
Kane Hodder (famous for portraying Jason Voorhees), who did stunt work for the movie, also had an uncredited role in the film as Frankenstein's monster.
The house in the opening scene was also used in Willard (1971) and Witchboard (1986). It has since been "retired" as a filming location.