Revealing mistake: When Leslie is fighting the soldiers, one soldier hits a second soldier with his rifle. The rifle can be seen to bend around the soldier's body and then straighten again. (02:12:10)
Revealing mistake: In the shot of Prof Fate evading the Indians while heading into Boracho, the long view shots show his "smoke screen" encompassing the car. In the close ups (obvious blue screen type shot) there is no smoke in the car.
Revealing mistake: In the final shot of the film the model makers neglected to include the antenna at the top of the Eiffel Tower, seen previously on the real tower in the establishing shot of Paris. (02:31:20 - 02:37:10)