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 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 Valentine climbs up to get Edgar you can see a green mark under Edgar's shoes. When we see Edgar lying in the car the green mark is gone. (00:13:40)
Continuity mistake: When Val is climbing up the electrical tower to get Edgar down, at first the sky is blue, then suddenly it's overcast. (00:13:40)
Continuity mistake: When the worker is drilling the ground you see his mouth is clean. When it cut, his mouth is now covered in mud. (00:17:15)
Continuity mistake: At Dr. Jim's when he is standing by where the generator should be, you can see several items around. When it cuts all the items has moved. (00:22:40)
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)
Revealing mistake: When Dr. Jim and his wife are backing away from where the generator was, you can see the ground behind them is flat. When it cuts, there is suddenly a pile of sand on the ground. This pile is hiding the hole that Jim falls into. (00:23:35)
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)
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 Val, Earl and Rhonda are on the rock and decide to pole vault off, Rhonda's backpack is flat when she scrambles down the rock, but appears full once she reaches the bottom. (00:40:20)
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)
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 Walter names the monsters Graboids he puts his hands down. When it cuts he holds both arm against his waist. (00:45:05)
Continuity mistake: In the scene where Walter is being attacked by the Grabbloid, the blood coming from his nostrils, and blood on his upper lip, changes between the first and second shot. (00:51:20)
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)
Factual error: When Val is talking to Burt on the CB radio and desperately trying to tell him to get out of his basement, Burt is using a handheld CB. After Val's very last transmission, Burt is now holding a rifle, not the CB. When the Graboid crashes through Burt's basement wall, we hear him say over Val's CB, "Jesus Chr..." his transmission was cut off. First of all, Burt wasn't holding the CB so he wasn't transmitting at the time. Second, there are portable CBs that you can lock the PTT button for extended transmissions (I owned one), but that wasn't the case here. Finally, even if by some chance Burt accidentally did lock the PTT button before putting it down, it wouldn't have cut off. The Graboid broke through away from where Burt was standing and talking and couldn't affect the CB. It was done for dramatic effect of the scene. (00:58:30)
Suggested correction: Could be he put the CB down on the PTT button (it's a rather large one) and it stopped transmitting when the tremors caused it to flip off it.
Continuity mistake: When all pole vault, Fred is holding the pole in his right hand palm up. Then he goes 1/2 the distance and returns to the start but his right hand is palm down. (01:00:00)
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)
