Revealing mistake: When the lawn mower the heroes send off as a diversion crashes you can see a wire pulling it. (01:01:30)
Audio problem: Right after Bert kills the second graboid he gets on the radio and says "we killed that mother-humper". Val replies "...be advised there are two more mother-humpers". However Val's lips don't seem to be saying "humper". This occurs even in unedited versions of the film. (01:01:40)
Revealing mistake: Near the end, Val, Earl and Rhonda are way off the rocks after the blast. When the monster comes up out of the ground and Val takes off, you can see the "ground" bounce. It's definitely a false ground so they can get the "graboid" pushed up through it. (01:24:10)
Revealing mistake: When the horse is lying on the ground with the tentacle wrapped around it, you can see a wire to the left of the screen attached to the horse. (00:31:00)
Visible crew/equipment: Look over Val's right shoulder as Rhonda is supposedly driving upside down with her legs sticking out the back window of the truck cab and you can see a man driving for her. (00:42:40)
Continuity mistake: When Rhonda climbs out of the ditch with Earl, where the graboid has killed itself, her backpack is slung over her right shoulder and hanging in front of her. In the next shot when she's standing up, the backpack is on her back.
Continuity mistake: When they are picking up Burt and Heather, Burt throws a sack to Val. When it cuts Val catches a totally different sack. (01:15:07)
Revealing mistake: As the last Graboid falls off the cliff at the end, just before it hits the ground, you can see its skin has already been cut up for the "blood" to gush out of upon impact. (01:25:20)
Continuity mistake: When Rhonda, Earl and Val are pole vaulting from rock to rock, if you look closely you can see that the poles are a lot longer than when they first picked them up off the ground. (00:40:30)
Continuity mistake: When Val and Earl are being chased by the graboid in the first shot it appears that the graboid is going perpendicular to the fence (you can see this because of the wires that cross it). But in the next shot the graboid appears to be going parallel to the fence. (00:33:20)
Suggested correction: The graboid made a turn.
Continuity mistake: When we see Rhonda placing a sensor to the ground we see her throwing her cap to the ground. When it cuts the cap has moved closer to the hole in the ground. (00:08:25)
Continuity mistake: When they all are trying to lure the graboids away from Val, Rhonda looks down the pipe running down the from the water tank. A piece of cloth soaked in water is tied around the pipe and water is dripping from it. When it cuts to Rhonda climbing down the water has stopped dripping. (01:08:45)
Factual error: Throughout the entire film Burt holds all of his rifles' butts underneath his armpit, rather than against his shoulder. A trained "survivalist" such as him would surely know better. Holding the "elephant gun" in such a way would most likely break his arm, wrist and hand when it fired. (00:58:20)
Continuity mistake: In the movie, Earl's last name was Basset, but in the credits, his last name was Bass.
Continuity mistake: When the snakeoid is chasing Val and Earl after they lose their horses, they run along a fence and the monster causes all the fence posts to fall over backwards. But shortly after, all the fence posts are seen to be upright, although some are tilted a little to the right.
Suggested correction: We only see 4 fence posts fall over in total. Considering there are probably 50+ fence posts there, I don't see how this can be an error.
Continuity mistake: When Valentine and Earl gets to Chan's, you see Heather packing some stuff into a box. She then takes a ketchup bottle in her left hand and a spray box in her right hand. When it cuts she is holding the ketchup in her right hand. (00:07:30)
Continuity mistake: When Dr. Jim and his wife are backing away from where the generator was, you can see them moving towards the car behind them. When it cuts, they are now facing the car. (00:23:35)
Continuity mistake: When Val's bomb gets spat back to the rock and scatters the gang, three of them wind up far away from the rock - too far to have made it in the time of the scene.
Continuity mistake: At the end, as Val and Rhonda are talking, Val's hat brim is flat. Rhonda walks off, and Earl slams the hood of the truck. When they show Val again, the brim of his hat is curved upwards.
Continuity mistake: When Val drives the dozer to get Rhonda off the water tower, he has the bucket up for her to get down. After she's safe, he drives on, and the bucket is down without his having lowered it.
