Other mistake: An antenna can be seen on the building above the grain warehouse.
Continuity mistake: Near the end of the film, Errol Flynn begins to sword fight with a pirate inside the cabin of the ship. Flynn backs the pirate outside onto the deck. When the scene changes to the deck, Flynn is fighting an entirely different pirate.
Factual error: Since this film serial was made in the early 1950s there are many scientific inaccuracies about the moon in it, not the least of which is that, according to the story, the moon has exactly the same gravitational pull as Earth.
Other mistake: During the car chase an Indian shoots an arrow that bounces off the car's license plate and comes back and hits the Indian. But a second before the arrow hits the Indian you can see him sitting on his horse with his eyes closed and a look of pain on his face as though the arrow had already hit him.
Other mistake: Before the trial by combat, when Richard Taylor and George Sanders choose their weapons, they are brought to them on their shields. But this happens to quickly, right after the choices were announced, as if predetermined.
Revealing mistake: The Cliffhanger Ending of Chapter Three has Commando Cody trapped in a van that the villains jump out of before before the van goes off a cliff. As the van approaches the cliff there is a driver-eye view, you can see tire tracks from other takes of this scene. (00:46:50)