Continuity mistake: In the briefing room, Hengist and the Prefect are sitting in chairs against the wall at least a foot apart, with bright overhead lighting that casts no shadows on the wall behind them. When we cut to a two-shot of them, however, they're suddenly shoulder-to-shoulder with almost no space between them, and the lighting changes to cast very dark shadows behind them. (00:28:20)Jean G
Continuity mistake: After Edith stumbles and nearly falls down the stairs, she still has both her shoes on. But after the kiss, she proceeds up the stairs and is now carrying one shoe. She had no time to take it off, as she was, er, busy with Kirk the whole time. (00:43:55)Jean G
Continuity mistake: As Balok's 10 minutes are counting down, McCoy comes onto the bridge wearing a standard blue velour uniform. A few minutes later, when Spock says he can bring up Balok's image, McCoy is suddenly wearing his medical tunic with the different fabric and collar. Then when Bailey starts losing it, McCoy is back in the regular velour costume again.Jean G
Continuity mistake: Kirk calls Scott to beam up, and lowers the communicator from his face as he looks at McCoy. In the next shot, he's holding it to his mouth once more. The shot changes one more time, and it's lowered again. (00:31:55)Jean G
Continuity mistake: The giant rock sitting on the promontory, in long shot, is much larger than the Kirk stand-in stunt man who climbs the rock face to reach it. Next shot, when Kirk pushes the boulder over the edge, it's suddenly much smaller than he is. When it lands on the Gorn, the rock is even smaller - now less than half its original size. (00:31:35)Jean G
Revealing mistake: Zarabeth tells Spock that Zor Khan only left her what was necessary to survive in the ice age. Mascara, eyeliner, lipstick and hairspray were apparently considered survival necessities. Yes, we know the actress "had" to wear make-up. But in a prehistoric setting, it shouldn't look as though she did. She could and should have been given a more "natural" make-up job - and an unlacquered hairdo. (00:38:25)Jean G
Continuity mistake: Towards the end of the episode when the Enterprise is moving leaving from the starbase, the ship is at an angle to the camera pointing to the right of the screen. The starbase behind it gets smaller and goes up a little. If the Enterprise were leaving the starbase at that angle, the starbase should have moved to the left and then completely off the screen.
Revealing mistake: When Kirk and Spock answer the intercom in the ship's corridor, Spock's uniform has a large brown coffee stain on the front. (This was digitally removed in the DVD release, but is still visible in the newly-syndicated "computer enhanced" version.). (00:17:00)Jean G