A horror movie has certain rules. If you break too many the audience will be disappointed.
This is a very short, no fluff, blueprint of how to write a horror script.
1. The Hook. Start with a bang. Step right into a suspense scene. (“Scream” opens with a terrifying sequence with Drew Barrymore on the phone with a killer)
2. The Flaw. Introduce your hero. Give him a flaw. Before you can put your hero in jeopardy we must care for him. We must want our hero to succeed. So make him human. (In “Signs” Mel Gibson plays a priest who has lost his faith after his wife died)
3. The Fear. A variant of The Flaw. The hero has a fear. Maybe a fear of heights, or claustrophobia. (In “Jaws” Roy Scheider has a fear of water. At the end he has to conquer his fear by going out onto the ocean to kill the shark)
4. No Escape. Have your hero at an isolated location where he can’t escape the horror. (Like the hotel in “The Shining”)
5. Foreplay. Tease the audience. Make them jump at scenes that appear scary — but turn out to be completely normal. (Like the cat jumping out of the closet) Give them some more foreplay before bringing in the real monster.
6. Evil Attacks. A couple of times during the middle of the script show how evil the monster can be — as it attacks its victims.
7. Investigation. The hero investigates, and finds out the truth behind the horror.
8. Showdown. The final confrontation. The hero has to face both his fear and the monster. The hero uses his brain, rather than muscles, to outsmart the monster. (At the end of “The Village” the blind girl tricks the monster to fall into the hole in the ground)
9. Aftermath. Everything’s back to the way it was from the beginning — but the hero has changed for the better or for the worse. (At the end of “Signs” Mel Gibson puts on his clerical collar again — he got his faith back)
10. Evil Lurks. We see evidence that the monster may return somewhere..somehow..in the future..(Almost all “Friday The 13′th”-movies end with Jason showing signs of returning for another sequel)
Go for it. Good luck!