Plot hole: When Jamie and Cully go on the offensive, Jamie lures a quark away from a drilling site into a narrow valley, then Cully drops a boulder onto it. Yet when we see the crushed quark, it is next to a drill, on flat land.

Continuity: At many points in this story there are problems with the costume that Zoe is wearing...the zip is often jammed part or all the way open. Not only does this leave most of her back exposed, but the position of the zip tends to change position during scenes, as while off camera Zoe tries to pull the zip back up, only for it to open up again minutes later. (It is a little unkind to say it, but possibly the costume was a little bit too tight for Zoe, causing it 'self unzip'?).

Factual error: The chart of the radiation on the island is wrong. The dialogue says it has steadily decreased over the past 172 years then suddenly disappeared. But the chart says it initially dropped rapidly for a few years, then started to fall at a slower rate for about a hundred years, then changed again and dropped to zero over fifty years. However, the way radiation disperses is anything but steady. It will continually slow down in its dispersal, forming a curve on a graph.

Continuity: Near the end of episode three, Jamie starts to read the printout. At first, he is reading the printout the right way round. But when we next see him, he seems to be reading it upside down. Then the third time we see him, he is back to reading it correctly (right way up).

Other: The Master says he wrote 5,000 words a week for 25 years and Zoe says "but that's over half a million words." Yes it is, to be exact, six and a half million words. (5,000 x 52 x 25 = 6,500,000).

Continuity: When the TARDIS breaks apart and the console sent spinning off into space, Zoe is lying on it. In close-ups she lying on her left side facing towards Jamie (who is opposite), but in the distance shots done with small models, she is lying on her right side facing away from Jamie.

Continuity: This story starts off where the previous story ('The Dominators') finished, but Jamie says something completely different to alert the Doctor to the approaching lava flow.

Other: When the Doctor pulls Zoe and Jamie back into the TARDIS, look at the scanner screen. It has the words 'Producer Peter Bryant' written on it.

Revealing: The Cyberman that falls from the roof in the final episode is obviously an empty costume. (This is another example of a mistake being repeated from an earlier episode. See the earlier story "Tomb of The Cybermen" for a note about the SAME 'revealing' mistake happening).

Audio problem: The first victim of the hypnotic signal stops walking when he hears it, but the sound of his footsteps continues for several seconds afterwards.

Continuity: Patrick Troughton's sideburns keep appearing and disappearing, depending on whether what is being shown is location filming or studio.

Revealing: When Jamie is wrestling with one of the Ice Warriors in a storage room, one of them gives the wall an almighty knock and it nearly falls down.

Plot hole: The map of the "War Zones" where the Aliens are conducting their War Games can be seen several times in this story. The map is visibly divided into 11 zones. Yet, during this story, the "War Zones" visited or referred to total THIRTEEN.

Plot hole: In episode seven the Doctor says that he is sending Zoe and Russell back to the 1917 (World War I) zone, but instead they arrive in the American Civil War zone.

Plot hole: Despite being asked to memorise all the locations and war zone commanders, Zoe's photographic memory lets her down: her first words to the Mexican leader are 'Who are you?'.

Continuity: The end of episode 7 does not match the reprise of the story at the start of episode 8. The Doctor, Security Chief and guards file into the SIDRAT in a different order.