Continuity mistake: When Shelly and Vera get into the car after their run-in with the biker gang, you can see the area around where the windshield wipers are attached to the bonnet is all perfectly painted. However after Shelly reverses into the motorbikes, it cuts to Shelly and now there are large areas of rust around the wipers. (00:31:30)Hamster
Continuity mistake: When the "stoned" couple makes popcorn, it is shown being poured from a pot on the stove into a bowl, cooked properly. A short time later when Chris and her boyfriend are searching the house they come upon the pot of popcorn on the stove burning, and they empty it again.
Continuity mistake: When Harold is at the toilet you can see a shelf behind him with a fire extinguisher and a piece of cloth on it. Also the shelf is by his waist level. A moment later the extinguisher has changed, the piece of cloth is gone, the shelf is by his shoulder level and a clock has suddenly appeared on the wall. It is obvious this is a change of stage scenery. (00:13:15)Mortug
Factual error: Jason picks up a red hot poker from the fireplace and it sizzles. Fire pokers only sizzle if they touch something. (01:08:56)
Visible crew/equipment: When the gang get out of the van when they arrive at the camp, Chris tells them that she is going to take a look around. She then opens the rear door of the van and you can faintly see a reflection of a boom mic. (00:22:15)
Continuity mistake: Jason's left eye is much lower on his face than his right eye, but it sits in a normal position behind the hockey mask.