I'm a big fan of giallo movies, and lately I have become a fan of director Bava, but this film is simply mediocre. This Bava slasher is best remembered for influencing other movies in the subgenre (the "Friday the 13th" movies in particular), but the truth is that it is almost unwatchable. I've been very pleased with all the films made by Bava that I've seen, but this one has to be his worst movie. It is a tepid, overcomplicated and downright silly horror film. Imaginative murder sequences aside, it is a real mess. It is confusing for no apparent reason. I'm not sure what Bava was trying to do here, but it is a real letdown from a filmmaker that should know better. The ridiculous ending is so bizarre that I wondered if Bava was responsible for it. It is just an awful movie, so you've been warned. The uncut version of the film is titled "Twitch of the Death Nerve", but I do not think a few minutes of extra gore can improve such a sloppy made movie.