Why scenes were filmed but were edited out
Working here and there in film business I know a few things!
Now this is why I think somethings were cut from "Prom Night" & you will be surprised! I have a feeling the main purpose why scenes were most likely cut to keep the cost down. Let me explain
Some Independent films companies (like the one that made Prom Night) always kept their films to no more then 90 minutes. They did this because a film could fit in one shipping canister (aka Goldberg Can). Over 90 minutes it would be 2 (Goldberg) cans and that would cost more money for prints and shipping! If the film ran over 90 minutes the cost of shipping the film to theaters would go up an additional 30% or more depending on the length. It did not matter if the film ran 91 minutes or 180 minutes a film over 90 minutes would ship in 2 Goldberg Cans. So to save money these companies made movies that were no longer then 90 minutes. I believe this was the case for "Prom Night". We know certain scenes were shown on NBC TV BROADCAST but those scenes never shown in theaters.
For all we know the original directors cut could of been 100 minutes or longer. I am sure the director knew his film could only be 90 minutes so what was cut was most likely his choice.
Today's films are now coming to most theaters in a digital format! (A HARD DRIVE) and length of a film is not a problem as it once was however the films are not better either. In fact most films today are too long..
PS I think the original intention of this film was not to have a majority of the credits happen during the opening scene. I have a feeling the film was meant to start with the scene with kids in the house and then credits were to roll shortly after the mother arrives at the home and finds out her daughter is dead. Then the credits would roll.
But to keep the running time to 90 minutes they resorted to plan B. That was to have credits rolling over the opening scene saving 3 minutes of running time.
This is only speculation