Continuity: Korob uses his wand to put a feast on the table and light the candles. Only, in the very next, close-up shot of him, the feast is gone and the candles are unlit again. Next wide shot, everything is back.

Revealing: Near the end of the episode, after Kirk has destroyed the orb, we see Korob and Sylvia in their true form. As they move, you can see the black strings used to manipulate the puppets.

Continuity: When Sylvia angrily upbraids Korob for talking too much, an inserted reaction close-up of him makes the table and chairs change from in front of him to behind him and back between shots.

Continuity: Norman is behind Uhura and Chekhov, but when Harry Mudd walks up to Spock, Norman is now behind android 2 and Spock.

Continuity: The shiny gold blanket covering the dying Commissioner Hedford is tucked up to her neck in close-ups, but only reaches her upper waist in full shots.

Continuity: In one scene the Enterprise's phasers were pink instead of blue.

Continuity: Just before Kirk kicks his attacker for the final time during the fight in the corridor, the Andorian picks the knife up off the deck with his left hand. In the very next shot, the knife has instantly switched to his right hand.

Continuity: When Sarek enters the banquet room to take his medication, the Tellarite sitting at the table holds a glass in his right hand. In all the full shots with Sarek in the foreground, the glass switches to the Tellarite's left hand. In all the close-ups of him, it's back in his right again.

Revealing: In McCoy's video of the Capellans, the weapon thrown at the sapling actually misses it and nails a nearby bush instead. The tree, however, obediently breaks in half and falls over anyway.

Continuity: During the coup attempt, one Capellan fights with the leader and gets stabbed. Before and after he is stabbed, the man's outfit changes entirely (look at the fur scarf, which goes from white to red.)

Continuity: Kirk's arrow strikes the Klingon in the knee. But a few shots later, the shaft is protruding from his thigh, several inches above its original position. Still later, he's holding one hand to his calf just below the knee, which isn't where the arrow was either time.

Continuity: Before the Capellans reach him, the Klingon's body moves into a completely different position, and to a different spot on the ground, than it was in when he first fell.

Deliberate "mistake": When the decoyed Enterprise heads back to Capella, the special effects shot is reversed to indicate that it's going back in the other direction. Unfortunately, this gives us two brief shots of the ship with the registration numbers backwards.

Continuity: When the Klingon shoots Maab with a hand phaser, the beam is yellow as he fires, but red when it strikes Maab.

Continuity: The Romulan vessels fire plasma weapons (as seen in "Balance of Terror"), but when they hit the Enterprise they become photon torpedoes.

Continuity: The aging Kirk's hairline has receded considerably. When he ages still more and goes completely gray, however, the receding process inexplicably reverses itself, and he suddenly has much more hair on his forehead than before.

Continuity: At the end, when Kirk and Garrovick are beamed up seconds before the explosion, Kirk is holding his communicator up to his mouth with both hands. But when they finally materialize on the Enterprise, Kirk's hands are down at his sides: no communicator in sight.

Continuity: Dr. McCoy's medical tunic had an engineering patch on it instead of the science patch it should have.

Continuity: 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.

Continuity: The ID cards Kirk puts into the computer to verify their identity appear/disappear in close/long shots.