Visible crew/equipment: When Doug spots his baby daughter through the window in the house, the child starts to roll off the bed and the hand of a crouching crew member comes into shot to stop the child from rolling off the bed completely.
Continuity mistake: As Brenda leaves the table asking "Does anyone need anything?", we see Bobby sitting by the table. When it cuts Bobby suddenly got something between his lips which weren't there before.
Visible crew/equipment: In the panning shot of the "Gas Haven" garage, the camera pans towards, and passes a car. As it pans past the car, the whole camera crane and crew are reflected in the car window. (00:05:00)
Continuity mistake: At the end, when Doug fights with Lizard, Lizard hits Doug in the face in one shot, and Doug's glasses fly off, onto the floor. In the next facial shot of Doug, his glasses are back on. (01:34:20)
Continuity mistake: When Ethel, Lynne, Brenda and Bobby are sitting around the table outside the caravan, talking, the position of the juice pitcher, ketchup bottle and mustard bottle constantly changes. (00:27:30)
Visible crew/equipment: When Doug attacks Cyst, he stabs his pickaxe into Cyst's back and he falls down from the car hood, to the floor. In this shot you can see the cameraman reflected in the house door glass. (01:26:25)
Continuity mistake: When Doug is fixing the system in the camper van while Lynn is speaking to him, he lowers his arms down from the system. Then as Lynn walks over to him, holding baby Catherine, his arms are instantly back up, tampering with the system again. (00:09:40)
Continuity mistake: When Brenda is talking about having "the chronic", Bobby says "Who smokes pot?" As Bobby comes out we see Brenda with both her arms down. As it cuts she is suddenly drinking from her glass.
Continuity mistake: When the gas station attendant is sitting at the table going through the bag, he has a cigar in his mouth, but it is not smoking. In the next shot it is instantly smoking heavily. Then, in the next shot, instantly, the cigar vanishes from his mouth altogether. (00:07:50)
Revealing mistake: As Bobby and Brenda are loading the bodies into the van, Lynn can be seen breathing.
Continuity mistake: Ethel's nightdress has a blue dotted design on it, visible when Lizard shoots her in the caravan. Later in the movie when she is being eaten by another mutant, her nightdress is solid white. (00:56:50 - 01:31:40)
Continuity mistake: At the start, one of the mutants swings a pickaxe into the back of the head of one of the researchers and it goes through their helmet. In the next shot when he hits the floor there is no hole. (00:01:45)
Other mistake: When Lizard enters the trailer he closes the trailer door. When Lynn runs towards the trailer and enters it the door was already open.
Revealing mistake: When the dad goes back to the gas station and finds the attendant in the outhouse, when he shoots himself his head blows a split second before the gun is actually fired.
Continuity mistake: When Brenda saturates the tire with lighter fluid, right before she lights it, it turns to burn gel.
Continuity mistake: At the very end of the movie, when Doug returns with the dog and the baby, the survivors have a big hug. Then the camera pans out and we discover someone is watching them. When the camera pans out there is absolutely no sign of the trailer that just blew up or the car.
Continuity mistake: When Lynn is retrieving the dog from inside the gas station attendants room, the dog messes up the window blinds. Between shots the position of the blinds in front of the window change, as Lynn turns around and is startled by the attendant. (00:14:05)
Continuity mistake: Soon after the car crash in the desert, the mom is seen bringing out deck chairs. She brings out two (one dark blue one and one light blue one) and leans them up against the campervan. But in the next shot the light blue one which was in front of the dark blue one has vanished. (00:22:25)
Visible crew/equipment: In the closeup of Brenda getting out of the blue car after the crash, as she opens the car door to get out it swings far enough to reflect multiple crewmembers (one wearing a headset) in its shiny blue surface. (00:19:35)
Continuity mistake: When the gas station attendant returns to his house, he finds a bag sitting on the porch. After he goes back inside, between shots the position of the bag completely changes. (00:07:35)
Answer: Pluto puts his hand over Brenda's mouth and Ethel doesn't bother to look over.