Continuity mistake: When El Blanco is outside Burt's home, and leaves, there isn't any hole in the ground after him. Later, in the movie, when El Blanco gets underneath the earth, he leaves a big hole after him. Why wasn't it like that the first time?
Factual error: Burt claims his watch updates its time "by connecting directly to the cesium clock in Colorado via ultrasonic frequency." Later the graboids home in on him by the ultrasonic sound emitted by his watch. Firstly, radio controlled watches update their time by receiving signals, but they don't emit any signals - the battery would be way too weak for two-way communication. Secondly, they work on radio waves, not sonic waves. Thirdly, if a hypothetical time transmitter did work on ultrasonics, the smallest distance between Colorado and Nevada is some 435 km (around 270 mi). An ultrasonic signal strong enough to reach that far would probably be deadly within a sizable range around the transmitter. (00:08:20)
Continuity mistake: When Burt is at the gas station, he makes change with the box top of the pump. he closes the box. Jack approaches to meet him and the shot cuts to Jack and the rock is all ready on top of the box. we cut back to Burt and he is placing the rock on top of the box.
Continuity mistake: When Burt's truck goes off the cliff and they go to the hill to find Miguel and his truck side-by-side. The truck now has different rims than before.
Continuity mistake: In the first Tremors when driving into Perfection the city limits sign list the elevation as 2135 feet. In this film the same sign shows the elevation at 2835 feet. In subsequent films, including the TV show and the Tremors 4 prequel, the sign says 2135 feet again.
Visible crew/equipment: Both times Melvin shows up and talks with Burt, we see the camera equipment reflected in his SUV's side.
Factual error: When Miguel gets knocked over the hillside by the ass-blaster, the camera shows how/where he falls - the speed of his fall is no more than 1/3 of how a body would really fall. Also, he falls right next to the cliff; bit when the gang goes down, he is right behind the truck, which we know is about 50-60 feet away from the cliff.
Audio problem: When the guy in Jack's truck says "You better pay for that camera", his mouth doesn't match his words.
Continuity mistake: After Jack digs down to the graboid he throws the shovel down, the next shot the shovel has moved next to the chainsaw.
Continuity mistake: When the graboid pops up surprising the group in the rocky area, it has a pair of animal legs in its mouth, and starts to swallow them. After an angle change, the legs are going into the graboid's mouth again.
Audio problem: The federal agents from various agencies show up and basically prevent the townspeople from killing graboids, and they're arguing with Burt about it. One of the government agents yells something, and it is loud enough to clip the audio (distortion).
Continuity mistake: When the gang first meets an ass-blaster, it flies into the sky, circles back and flies down towards them, quickly. The camera angle changes to its point of view, and for several seconds the view does not change - as if he'd just stopped in mid-air.
Other mistake: When Jack is using the chainsaw to dig Burt out of the Graboid, we do not see where he is cutting, but we do see sparks fly just before he stops and puts the saw down. The chainsaw angle does not match the sparks' direction.
Continuity mistake: When the government guys come into the store in the evening they arrive, the wall clock shows 8:20, but the head guy's watch shows 6:28.
Suggested correction: I can't remember the last time I went into a house and saw a working clock on the wall. Very simple to explain, they just haven't changed the battery in the clock due to sheer laziness.
Visible crew/equipment: When the government guys first show up, we can see the lighting rig reflected in their sunglasses.
Revealing mistake: When the group comes across the first ass-blaster, it hops out from behind the fence. Pay attention to its right leg when it jumps out and you'll see a rock on the ground just appear behind it. After it spots them, it stomps a few times. While it's stomping, pay close attention to the rock and you'll see it and some of the ground around it just disappear after a few frames. This rock also isn't visible in any other part of the scene. (01:01:10)
Other mistake: If the flying creatures sense heat, then the junkyard should have a lot of heat signatures, but the aerial photograph has none.
Suggested correction: It wasn't an actual, fully operational junk yard with car crushers, cranes etc. It was just an area that the residents had designated a junk yard.
Continuity mistake: In the final scene, when Burt leaves Melvin on the rock with El Blanco nearby, Burt says goodbye to Melvin and begins driving away. His door is wide open as the car begins moving - the camera angle changes and it's now closed.
Factual error: Burt hands a bolt-action rifle to Jodi when the group heads to the canyon to clean up the Shriekers, and she ends up using it to fire at the first Assblaster they encounter. She begins rapidly firing off rounds from this rifle as if it were a semi-automatic rifle, not the bolt action, single shot rifle that it is.
