Many viewers have speculated that the character of Dr. Krueger and the boiler room scenes are references to Nightmare - Dal profondo della notte (1984). However, this film was shot in 1983; a year prior to Nightmare's filming in 1984.
Originally released in both 3-D and 2-D.
Filmed in New Jersey in 1983 under the title "Dark Sunday." Other alternate titles included: "Beautiful Screamers", "The Omega Factor", and "The Nightkillers."
Of the additional US $10,000 that actress Lynn Redgrave wanted, producer-director Simon Nuchtern said in an interview published on September 9th, 1984 in The New York Times: ''If I had $10,000 extra dollars, I'd put it into lights. Not one person is going to say, 'Go see that movie because Lynn Redgrave is in it.' But if we don't have enough lights and that 3-D doesn't pop right out at you, people are going to say, 'Don't see that movie because the 3-D stinks.'''
This movie was part of an early to mid 1980s cycle of 3-D movies. These included: Starchaser: La Leggenda Di Orin (1985), Tempesta metallica (1983), Lo squalo 3 (1983), Mutanti (1982), Amityville III (1983), The Man Who Wasn't There (1983), Silent Madness (1984), Rottweiler - Cani assassini (1983), Comin' at Ya! (1981), Week-end di terrore (1982), Il cacciatore dello spazio (1983), and Il tesoro delle 4 corone (1983).