Other mistake: Kirk's voice-over log entry says he's been "placed on the surface of an asteroid." The Metrons earlier referred to it as a planet prepared for them with a suitable atmosphere. How and why does Kirk suddenly assume that it's an asteroid rather than a full sized planet? As an experienced space veteran, Kirk, who has already been told that it's a planet, would never make such a mistake. (00:23:45)
Tomorrow is Yesterday - S1-E20
Other mistake: In the end credits the character of Captain Christopher is credited as Major Christopher.
Tomorrow is Yesterday - S1-E20
Other mistake: The Air Force police officer (played by Hal Lynch) was beamed up from inside the records room (after finding Kirk exiting the dark-room) but was returned outside the room... so he was physically transported INTO himself (as opposed to replacing the beamed-up future version at the exact moment and place he was removed as they did the pilot, Christopher).
Other mistake: Ben Finney's rank is stated as Lt. Commander. His rank insignia on his uniform shirt is that of Commander (The same as Mr. Spock whose rank is Commander).
The Return of the Archons - S1-E22
Other mistake: After Sulu is "absorbed", he is beamed up to the ship. After materializing, his demeanor could be described as calm, gentle, meek and euphoric. After that scene, the captain's log quotes Kirk as saying "Mr. Sulu has returned, but in a highly agitated mental state." Was Kirk looking at a different Sulu than we were? A gentle, meek and euphoric condition incorrectly being touted as "highly agitated"? Time for Shore Leave. (00:01:28 - 00:03:53)
The Return of the Archons - S1-E22
Other mistake: On the bridge, as the camera looks at the view screen, there is a flashing blue light reflecting on the console in front of Sulu, but there is no light other than scanner under the viewer flashing and it's too far away to project light that far, and it's amber colored.
Space Seed - S1-E23
Other mistake: Spock calls for McGivers and Scotty to the transporter room. In the Transporter Room, Scotty is at the controls, then after he went to the Transporter pad, they used a stock shot of his hands working the controls.
This Side of Paradise - S1-E25
Other mistake: After Spock is hit with the spores, he goes down on all fours in pain. As he writhes around, the skin tone of his ears is vastly different to his other makeup.
This Side of Paradise - S1-E25
Other mistake: As Spock and Kirk are fighting, Spock bends a steel bar with one of his blows. When he hits Kirk, though, it simply makes Kirk a little sore. A blow strong enough to bend a steel bar would shatter human bones.
Other mistake: Kirk and Spock stun two Klingon guards, yet despite being unconscious, the guard on the left jumps from the balcony and lands feet first on the ground. If he were really unconscious he would have simply tumbled down. (00:36:20)
Other mistake: When Kirk is lecturing Ayelborne in the council chamber, the actor behind him is mouthing Kirk's dialogue.
The Alternative Factor - S1-E28
Other mistake: When Spock calls Kirk to the bridge after he discovers the Lazarus energy source, he and Lazarus head to the bridge. There is a shot of McCoy standing in the corridor, and one of the red alert panels is burned out while the other is still flashing.
The City on the Edge of Forever - S1-E29
Other mistake: When talking to Edith Keeler one evening, Kirk refers to a star in Orion's belt, pointing it out. The shot then cuts to a scene of the horizon. The sky is quite cloudy and the light from the sun is still lighting the horizon. The stars would not be visible.
Who Mourns for Adonais? - S2-E2
Other mistake: The bushes behind the temple shimmer in time with the temple when the ship is firing on it, but they aren't connected to it.
Other mistake: When the Planet Killer hits the Enterprise, the ship lurches 45° to starboard, and the crew fall accordingly. However, the chairs, except for the communications station, stay in place.
Other mistake: When Norman goes to the second panel in Auxiliary Control, there is clicking when he turns his right hand, but there is no knob, just a blinking light.
Other mistake: The action is shifting back and forth from the bridge where the alien ship is attacking and sickbay where McCoy is operating on Sarek. In two separate takes when the scene shifts to sickbay McCoy is standing at the operating table. I noticed a wisp of smoke rising from McCoy's right side (left side of screen). It appears to be from a cigarette in an ash tray below camera level either beside McCoy or near the head of Spock's bed.
Suggested correction: This was an intended physical effect to simulate the cryogenic surgery that McCoy was performing on Sarek.
Other mistake: In the scene near the end when Kirk orders Kyle to beam Hengist into space, Kirk and Kyle say their lines in the wrong order. Roughly: Kyle: Don't get excited, Captain. I would have done it. Kirk: Spock, you do it.
The Gamesters of Triskelion - S2-E16
Other mistake: When Kirk agrees to fight in the arena at the end of the episode, he and the thralls are warned that touching an opponent's color will result in the loss of a weapon. Kirk does this several times during the fight, but isn't penalized in any way.
The Gamesters of Triskelion - S2-E16
Other mistake: Kirk tosses the Andorian, and as he hits the ground, his shirt comes up and the man's real skin tone is visible.
