Research - What makes a good horror film?

Death / Extremes not normally seen - SAW has been a great success and the franchise has released 7 films. Why it has been so successfull is the extreme gore used throughout the film. Victims are killed and tortured in sick and unimaginable ways which is needed in order to scare the viewer.

Sound Track: The sound tracks used in horror films is very important and could be argued to be the most important factor in making a horror film scary. When used properly it can create very scary climaxes in films and give the sense of fear on the viewer. Sometimes even the lack of soundtrack can be an excellent tool in creating fear.

Suspense / The Unknown: What users don't know or do not expect creates the sense of fear. Suspense is used extensively in horror films and is closely linked with the soundtrack in order to build it.