Revealing mistake: When Hiram, Juan and the boys are camping out on their way to the mine, one of the cowboys is hit by a couple of Dirt Dragons (one from either side) as he runs to the others. His body is tossed one way, then the other (as they hit him), but then sort of 'jerks up' against gravity, indicating he is being lifted by a wire. (00:24:55)
Revealing mistake: At the end of the movie, when the last "Graboid" appears, in one or two shots of him retracting back into the ground, you can tell the shots are reversed, as dirt is being sucked down in an unnatural way. It flies up and sort of "implodes" towards the creature. (01:23:50)
