Black Christmas is your standard slasher movie...except it takes place during Christmas. If you remember that one Urban Legend about 'The Calls coming from inside the house!" Black Christmas capitalizes on that.
The phone calls because increasingly creepy as the crawls goes on, too. Did I say crawls. Yeah, I meant to, simply because this movie moves so damn slow. Considering the pacing of the movie, it's pretty hard to believe that Television stations deemed it too scary for television in the 80's.
Now, I know in a lot of cinema, there are things that are left ambiguous or unturned for the viewer to decide. But, at the end of 'Black Christmas,' you realize that the cops haven't even checked the whole house, they leave Olivia open and vulnerable. What kind of shoddy Police work is that? Still, the ending is pretty memorable, if only for the sole fact that the killer is still out there.
Either way, besides the pretty slow pacing of the film, I still find this movie to be pretty enjoyable. There are many scenes of remembrance, mainly involving the POV of the killer in the house, the phone calls, and Olivia Hussey's acting is great. No matter what though...I still remember her from having to sit through that dreadful version of 'Romeo & Juliet' way back in the early days of High School.