Continuity: When Allison closes the door that her brother is pinned on, his eyes move as the door closes and back to their usual position when the door opens.
Continuity: When Dan tells Alison that he'll pick her up in an hour for them to go up to the mountains, it is broad daylight, but when Dan goes to pick up Alison, it is nighttime.
Continuity: When John is about to stab a doctor with a syringe the syringe's needle is crooked. In a subsequent close-up, the needle is straight.
Revealing mistakes: When Dr. Spires finds the body of Dr. Vaughn, the syringe in Vaughn's neck can be seen vibrating with his pulse.
Continuity: When Sheriff Stevens handcuffs Kirby, he clearly cuffs both of Kirby's wrists. When he helps Kirby up and takes him away, only one wrist is cuffed.
Continuity: When being stalked by Kirby at the institute, Allison hides in a storage room. Next to the outside door handle there is a light switch with a power indicator. When Kirby walks by, the switch is clearly turned on. When Allison leaves, the switch has been turned off. Also, despite being turned off, the lights are still on the in the room anyway when Allison makes her escape.
Crew or equipment visible: When Dr. Halman is talking with his wife about getting pizza, you can see someone moving in the window frame above Ron Silver's head.
Continuity: Towards the end of the movie, we seen John Kirby, covered in flames, jump into a near by lake. When he comes out of the water his clothes are not burned at all.
Continuity: John Kirby kills the mother in the corner of a bedroom at the start of the film. A few minutes later, Sheriff Dan Stevens enters the room, and the body is gone. But later the Sheriff says there are two people dead in the house, even though he's only seen one body.
Continuity: Bloodstain on the front of Kirby's shirt during the initial fight scene with Stevens while being arrested changes color, position and from wet to dry several times.
Continuity: During the fight in the bar, the biker gang leader is wearing a bandanna when he yells at the one of the biker girls for almost hitting him with a bottle. A moment later, when he gets on his bike and tries to run from Sheriff Dan, he's wearing a cowboy hat.