Came to attention of the British censors as a video nasty in the early 1980s mainly because of several gimmicks, which included providing a vomit bag with the video and a competition to guess the weight of a 'brain' in a jar.
Director Romano Scavolini claims that all the main special make-up effects for the film were designed and created by Tom Savini and only the prosthetic effects were done by other people (mainly the late Leslie Larraine). There are also photos placing Savini on set. Savini has distanced himself from the project and says that he was just a consultant for the film. Ed French (who supervised the special make-up effects for the New York sequences) also says that Savini didn't do any hands-on work, only giving advice and direction to the special effects crew.
Tom Savini is credited as the film's make-up effects artist. In fact he was only a consultant and threatened to sue over the use of his name to promote the film. Some video prints still bear Savini's credit as "Effects Director". The effects were actually created by Ed French.
When the young man is smoking on the stair, he is only wearing his underpants, the scene then cuts to his girlfriend taking a shower, then we see him back on the stair, smoking, and then he is wearing a t-shirt too.
What are the differences between the R-Rated and Unrated Version?
A
The ordinary slasher movie about a sick twisted serial killer has been released in two versions in the US: an R-Rated Version censored in violence and plot plus an uncensored Unrated Version. In the UK, only the R-Rated Version is available. Furthermore a less censored version by World Of Video 2000 was released on VHS but that release was banned and put on the list of "Video Nasties". A detailed comparison between both versions with pictures can be found here.