Other mistake: According to the plot, no life is possible in the Northern Hemisphere by the time the film is set. Yet, when the sailor who has been sent ashore to look around the San Diego refinery enters the premises (more precisely, when we see the smoking-prohibited sign on our right and his left) a bird can be seen flying in the upper left-hand corner of the screen.
Other mistake: The exhaust of the space ship is so strong that it knocks down Jeff and Paula to the ground, but their hair doesn't get changed at all.
Other mistake: When the Behemoth swims up the river & capsizes the ferry, a static model is used that bears no resemblance to the animation model seen throughout the film.
Other mistake: The Count and the Professor jump into the water to save themselves from the dinosaurs (which can't swim). In the long shots, it appears they are out very far, in at least six foot deep water, but close up, the water they are in couldn't be higher than four feet. What's to keep the dinosaurs from grabbing the two if they're in water that wouldn' come up to the dinosaurs' kneecaps?
Other mistake: A Telechron electric clock on the fireplace mantel keeps time even though the power has failed.
Other mistake: After the intro, one girl in the bar peeks from the window and goes; "Say, here comes Gordy and Jennie." And indeed the duo is getting off the car and joins them. The problem is, the window is on the opposite side of the entrance and there's diegetic music playing throughout the scene. In other words, she saw them parking to the left, but in a split second they are coming through a door on the right. (00:02:40)