Continuity mistake: At one point, the gigantic title character knocks over a city bus. For a moment, the word TONKA can be seen on the underside of the vehicle.
Continuity mistake: When the group go out to inspect the house damaged by the monoliths, the dirt around the rocks is white while the rest is dark. The professor squats down and picks up white dirt in his left hand and dark dirt in his right hand, then calls the geologist. In a close up, he opens his hands and the dirt colors have changed hands - the shot has been reversed.