Plot hole: The Doctor says the explosion of the sonic cone will destroy everyone, so why doesn't it?

Continuity: Due to some sloppy editing of the "cliffhanger ending" at the end of episode 2, and again at the start of episode 3, the Doctor, Mel and Burton are seen to freeze in place for no apparent reason, just BEFORE we see the Bannermen line up and aim their guns at them.

Continuity: The Doctor can be seen wearing glasses in some long shots of him riding a motor bike. Normally, Sylvester McCoy (who played the Doctor at this time) removed his glasses before filming. Seems as though he either forgot, or could not ride a motorbike without them.

Factual error: Why would a US satellite launch be "history in the making" in 1959? The first American satellite to reach earth orbit (Explorer I) was launched in early 1958.

Revealing: The bodies lying on the ground during the initial battle are rather too obviously rubber dummies rather than real people.

Plot hole: In episode 3, the swarm of "bees" attacking Gavrok and his men look nothing like real bees, being far too large when they approach the camera's position. (In fact, stock footage of a swarm of locusts was used.).

Revealing: At several points in the story the 'huge heavy ice cliffs' get blown fractionally upward by people running past them, showing that they are made of very thin, very light plastic.

Plot hole: At the end of episode 1, the 'cliffhanger' ending is that The Doctor climbs over some railings, and then, by looping his umbrella on the railing, he begins to climb down. He looks down and it seems to be a very long way down. This is resolved in episode 2 by having Glitz walk around and let the Doctor step on his shoulders. Not only is it silly, but because Glitz walked around, it also makes the previous 'cliffhanger ending' totally meaningless.