When Barnaby and Lois leave the car lot in his new car, they cut in front of a large truck that turns off the street as they enter it. Further down the road they are seen passing the very same truck off the left side of the road.
When one of the chimps gets out of her cage and messes around with chemicals, before the action cuts away to three scientists discussing a hair restoring formula, the large vial into which the ape has been pouring the chemicals is full to the brim. When it cuts back to the Chimp in the laboratory, the same vial is only 2/3 full.
When Barnaby and Edwina emerge from his office to see that Oxley and the other scientists are behaving like children, a panel in the 'wall' to the right of the door moves, and a gap can clearly be seen in the wall of the set looking into his office.