This is a surprisingly entertaining Italian giallo that resembles a lot of later American slasher movies more than it does the earlier or contemporary Italian thrillers. As in slasher films like "Stage Fright" (both versions), "Popcorn", and "Clown at Midnight" this film is basically about nine people who attend a showing at a mysteriously deserted theater and find themselves trapped inside and picked off one-by-one by a mysterious masked killer, who may be motivated by revenge. Really though the plot here is pretty inconsequential. This movie is much closer to the stylish gialli than amateurish slasher movies in quality, and instead of having a cast of adolescent American nitwits, the cast is made up of sumptuous European beauties who spend much of the movie in various states of undress--oh yeah, and the male lead from "South Pacific".
The most recognizable actress might be the Swedish Janet Agren who later appeared in Fulci's "City of the Living Dead", but she (and her obvious body double) are only in the movie briefly. The lead actresses are Paola Senatore (who later appeared in Italian porn movies) and Lucretia Love (who might as well have). Neither are great actresses but they easily fulfill the requirements of their roles here. (Senatore and Agren would appear together again later in Umberto Lenzi's cannibalism opus "Eaten Alive" where hilariously the blonde Aryan Swede and the swarthy Italian were supposed to be sisters). You may wonder what Rosanno "South Pacific" Brazzi is doing in a movie like this, but this is actually a step up from his previous appearance in "Frankenstein's Castle of Freaks" (and personally I'd rather watch either of these again than "South Pacific").
You might wait for this to be legitimately released on DVD, but unlike a lot of obscure gialli there are good-looking copies of it floating around out there.