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)RJR99SS
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)Mortug
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)RJR99SS
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.
Trivia: When Mindy is getting her picture taken next to one of the graboid's tongues, look at the shelf of movies behind her when the camera zooms out its farthest in that shot; in the second row down (I think it's the in the second row down), if you look really closely, you can see that one of the movies is Tremors. (00:25:40)