Continuity mistake: In the wide-angle shots of the blue Willys (Jeep) wagon, the windshield is a 2-piece version with a vertical divider in the middle. The close-up shots don't have the divider.
Continuity mistake: When JB is driving the truck and is being bombed with grenades from the helicopter, the truck gets smoke blackened. But when he arrives at the speedboat, all the smoke marks have gone.
Continuity mistake: When they arrive on the island of Talos, the bronze giant, Hercules and Hylus find the statues atop huge plinths. In close up, they are looking up at the statue of Talos, then in a wide shot they start to walk towards it across bare rocks, then in close up they are back where they were with plants behind them.
Continuity mistake: When Roger is in the van talking to Macdonald, his face is deliberately dirty and stubbled - but when they are about to shoot him, he is clean-shaven. similarly with his bruises which seem to magically disappear by the evening of the first day.
Continuity mistake: When Donovan is picking Miss Deddum off the ship, she loses her balance (and bag) and there are many outriggers near the ship. First the water is choppy, then Donovan says "watch these swells." The next second it's calm as glass when she steps off and he pulls her in the water. The next scene, everyone is jumping from the ship and suddenly, all the outriggers are nowhere to be seen near the boat.
Continuity mistake: Goliath's two new friends grab him by the arms and carry him between the horses to escape from the guards; as the bad guys give chase, there's no consistency between shots regarding the shadows; they gallop through shadow areas that are entirely exposed to the sun when the baddies are coming, and vice versa. (00:08:00)