Other mistake: The sphere operates through the opening and closing of Cavorite blinds to negate the force of gravity. It has no engines at all. Why then, when it lifts off from the moon, do you see a blast of what appears to be rocket exhaust?
Other mistake: The abandoned orbiter requires fuel to decelerate and drop out of its stable orbit. Mantee knew the orbiting spacecraft was out of fuel before leaving it, but he was still trying to give the craft voice commands to land some forty minutes into the film.
Other mistake: When Morgan is leaving his house at the beginning, he remembers to put the garlic back on the door. He drops his bag of stakes next to one of the bodies he plans to put in the back of his car. After putting the garlic on the door, he never picks the bag up. In fact, the bag somehow disappears in the process. It's not in the car, as you can see it's empty as he puts in the bodies.
Suggested correction: After he replaces the garlic, he is moving away from the door. There is a cut, and he is walking in the opposite direction away from the garage. There is obviously a time jump between the shots. He undoubtedly put the bag in the front passenger's seat.