Sheriff Brent Marken gets a call at 3:13am regarding the murder of the two high school students, but by the time he gets to the scene it is clearly daylight.
In the canteen the can of drink in front of the two girls changes from a regular Coca Cola to Diet Coke between shots.
When her boyfriend is attacked, Stacy is sure to lock the door. As the camera shows the door by itself, it is clearly unlocked.
When Jody is talking to Leonard Iveston, the word Byron is wiped out on the board behind them in the close up shots. When the camera goes to the long angle where most of the classroom can be seen, Byron is chalked onto the board again.
When the murderer is hacking down the front door with an ax, the door and its hinges change. In one shot the hinges are on the left (front view) and the door closes. The murderer then manages to hack through the door and the door swings open with hinges on both sides, opening like a swinging door from a western movie.
Three nights in a row there is a full moon, which is impossible.
During the final confrontation between Jody and the killer, she shoves the killer by the balcony fences. However, when the killer falls off the balcony, the fence in front that barricades the balcony has disappeared.