When they have landed on Delta 3 and met Nikki. Robots are attacking them, we can see Jason (left of screen) taking a spear from a Nikki's men. A few seconds later, we can see Jason taking the spear again.
When Omus is trying to kill Jason with the sonic device. Jason jumps on Omus and takes him down. Look closely, Omus has kept his anti-sonic helmet on his head. On the next scene, Jason is taking the helmet, now lying a few feet from Omus.
Near the end of the film when the base is collapsing around Jack Palance what appears to be a girder of some sort hits him on the head and judging by his reaction it wasn't supposed to happen.
In the opening lines of text with which the film begins, the word "it's" is misused (??"Man has moved onto the moon, colonised it's surface and erected..."). It should be "its" ("Man has moved onto the moon, colonised its surface...").