Good Example of Tension

One thing that makes a good horror movie is when what is happening on the screen is uncertain, or rather looks hopeless. When things are too close and a hair is the difference between life and death, it makes an audience pulled into what is happening. Makes them interested to see what happens and if the person will make it. Take for example, The Texas Chainsaw Massacre. If you haven't seen this movie yet, I'd suggest you watch it first before playing the video.

The young woman is injured and can barely walk, but still has to run away in a place where it appears there is no one around to hear you scream. She is being chased by two attackers, and one easily catches her. Its not a matter of getting away, she is practically already caught and he is just toying with her until the man with a lethal weapon that she cannot defend against catches up and kills her.

All these factors which a person does not stop to think about are subconsciously absorbed and processed through a person's brain, and make for an intense scene. Good intense scenes like this are the best for any movie, not just horror. Even as she climbs into the truck, you still think she might not make it, and feel a sense of relief when she does make it to safety.