This movie is really disappointing. But the opening sequence is excellent. Really. It has a great beginning. The introduction of the character is excellent. It has the right balance of horror and humor. It's believable. Everything about the opening scene is great.
And basically everything that follows is terrible. It seems like the screenwriter spent a good two or three months polishing off that first scene, and then spent two or three hours on the rest of the script. If you decide to rent this movie, just watch the first scene. Once the high school kids come on the screen, it's time to turn off the movie.