Continuity mistake: When Luther Blair and Captain Larson have been captured, the rest of the crew return to the ship. Later, Dr Higgins checks his watch. When the crew arrived at the planet they removed their spacesuits to reveal their short-sleeved shirts, yet the close up shows the watch below the long sleeve of his space suit, not just his bare skin.
Other mistake: It supposedly takes three weeks for the space ship to arrive at the 13th moon of Jupiter. Yet the people following their progress back on Earth stay in the same positions and clothing throughout all this time.
Continuity mistake: When Luther Blair rescues Captain Larson from his cell towards the end of the film they are both shown exiting the cell with pistols drawn and ready. When the shot cuts to the corridor outside both their pistols have now disappeared from their hands.
Visible crew/equipment: When the monster supposedly falls into a pit behind the altar at the end of the film, look at the left side. The mat the actor lands on visibly bounces into view.
