People who didn't like this movie...
..probably have very short attention spans. They probably expected to see blood and guts. Maybe they wanted the killer to be running around chopping heads off and stabbing people. It's possible that they also wanted gruesome dead bodies popping out of closets and tons of screaming. And finally, they most likely waited to see Jill and Tiffany get naked and make out, then get killed. Because THAT'S what makes a good horror!
You're dumb.
This movie was very good for the very fact that it WASN'T the typical whore-or movie. It was actually more suspense than anything.
When you go into a movie expecting certain things to happen, you will almost always be let down. Some of you need to chill out!