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)
Continuity mistake: Reba gets out of their truck at the compound and looks through the binoculars - in the foreground you see the tractor and trailer they use to escape are very close together, or are attached already. When Kevin Bacon and the other guy figure out to use it, the camera pans around and the tractor and trailer are 60-100 feet apart.
Continuity mistake: When Val and Earl are relaxing with a couple of cold ones after they bury the trash, Val's recliner chair changes. From the side it is a brownish-rust color cloth material. In the next shot, from the front view, it is greenish leather. This scene takes place after Rhonda's near miss with the graboid but before the first guy, old Edgar, is found dead.