Continuity: The gash on Kirk's right cheek disappears between the time he and McCoy fall asleep in the cave and when McCoy wakes up to find Kirk at Nona's side.

Continuity: When Nona is trying to seduce Kirk, we see a close-up of him with nothing on his shoulders. Cut to a two-shot and suddenly Nona's arms are over his shoulders and around his neck.

Continuity: Why does Kirk think a being of pure energy is "impossible?" They've encountered several such creatures in the past in "Metamorphosis," "Obsession," and "Wolf in the Fold."

Continuity: Kirk and Spock pretend to be filming Daras so they can enter the building where John Gill will give his speech. Look at the lamp Spock is holding. In the beginning it works, than a couple of scenes later it doesn't, and when they are outside the chamber where John Gill is, his lamp is on again.

Continuity: In a few episode we'll hear about "Hodgkin's Law of Parallel Development," but here Spock claims the odds of a planet developing similar to Earth's Nazi culture are "virtually impossible." Why was it so likely as to be easily accepted there, but impossible here?

Other: In the jail cell scene, when Kirk tears a strap from the bed, his left handcuff is open. It remains open for several seconds, while he tries to conceal it by moving his right hand to block the camera's view.

Continuity: When Scotty gets drunk and tosses an empty bottle away, there's a dubbed in sound of glass breaking, but when he collapses, the bottle is unbroken at his feet.

Continuity: Kirk and McCoy are in the Exeter's engineering section when Kirk uses the intercom to ask if anyone is aboard. Several shots of the deserted ship follow as his voice echoes off the walls, including one of engineering - with Kirk and McCoy suddenly, mysteriously absent.

Continuity: At the end, the flag is brought in, and Kirk stands up - but in the next close-up of him, he's sitting down again. Next full shot, he's standing once more.

Continuity: Near the end, when Cloud William opens "The Book," the red bookmark ribbon isn't in the spot he turns to, until the close-up of the page, when it suddenly appears there.

Plot hole: When M-5 destroys the ore freighter, Dr. Daystrom says, "Fortunately, it was only a robot ship." But Daystrom wasn't on the bridge yet when Spock announced that fact. He didn't have any way of knowing that the freighter was unmanned.

Continuity: The sword Spock is carrying disappears between leaving the cell and the group exiting down the corridor. No one else in the shot appears to have taken possession of it.

Plot hole: Scotty is receiving images of the launch, supposedly from an orbiting satellite. But many of the camera views are obviously from ground level, and couldn't possibly have been taken from orbit. It's not a rebroadcast from a ground camera, either. The implication is clearly that Scotty is is picking up a live satellite feed.

Revealing: Isis the cat was disinclined to hold still for special effects shots. When Gary Seven beams off the Enterprise with the cat in his arms, the position of her head jumps several inches as they're dematerializing.

Continuity: When Isis meows and enters the inner office, the door is open several inches and the lights inside the room are on. When Gary Seven follows her in a few moments later, the door has nearly closed itself and the lights inside are off.

Continuity: Spock claims that history is unchanged at the end of the episode according to the library tapes - how would he know? If history changed, the tapes would change too. And unlike in "City on the Edge of Forever", there's no Guardian around to keep people from being influenced by an altered timeline.

Continuity: When Kara renders the landing party unconscious, Kirk falls with his arms splayed out to each side. But in close-ups, he has one hand folded over his chest.

Revealing: "Trek's" new 3rd season uniforms were tighter-fitting than their velour predecessors, presenting a problem for some actors. When the landing party beams down in this episode, the outline of William Shatner's tummy-wrapping girdle is very visibly showing through his costume.

Revealing: After Kirk and the crew arrive underground, he stuns Kira and removes her bracelet. After he removes it, the unconcious woman quite deliberately lays her hand flat on the ground.

Continuity: When Spock orders the phasers to fire, they shoot outward from the ship at an angle from each other, but when they hit the asteroid they converge at a single point.