Continuity mistake: While Flavius guides Kirk, Spock, and McCoy to the city to find Merik, the foursome stop behind a group of trees. In the first wide shot, as Flavius explains they'll wait until dark, there are no red marks on the tree trunks, but in their closeups there are a few red marks (presumably from squibs), before the gunfire has even occurred. At the start of the second wide shot the tree trunks are still void of those marks, and when the police shoot at them that's when the red marks appear. (00:15:15)
Visible crew/equipment: After Kirk tells the policeman that he wants to see Merikus and "perhaps" he's a friend, the policemen lock the cell then leave, and when it cuts to a view of the cell from the side as Spock walks over to the steel bars, the overhead boom mic is visible inside the cell, over Spock. It's visible again, with a better view, when McCoy walks over to Spock beside the bars. (00:18:15)
Continuity mistake: After Spock talks about Sun Worship on the bridge, Uhura goes to correct him. As she's sitting at her console, her arm is covering the note board. When the angle changes to include her, Kirk, Spock and McCoy, her arm is above the note board. Back to a close up, and her arm's covering it again.
Continuity mistake: When Kirk, Bones and Spock are commanded to stop, and raise their hands, they do so. After a moment, Kirk starts to lower his hands. After the camera cuts to a shot from behind, Kirk's hands are by his sides and he goes for his phaser. After another warning shot, he says "I think he means it." The camera goes back to facing them, and his hands are up again.
Continuity mistake: While Kirk, Spock, and McCoy attempt to escape, Merik contacts Enterprise with the stolen communicator and the Proconsul stabs him, then when Merik tosses the communicator it lands in front of Kirk's feet in a closeup. The problem is that in the closeup Kirk is wearing his black uniform pants, but during this scene Kirk is wearing the light colored slave pants. Also interesting to note, when the sword landed on the floor in front of Spock's feet, the Vulcan is wearing black lace-up flat footwear instead of his black uniform boots. (00:46:35)
Revealing mistake: During the televised fight, in the wide angle shots, you can tell it's Spock's stunt double fighting.
Continuity mistake: The chain symbol on Kirk's shirt goes from dark to light and back several times.
Revealing mistake: Kirk uses a sword to cleave a Roman guard during his escape from the TV studio, but there is no blood on it. Later, though, when Claudius stabs Merrick in the back, there is blood on the knife blade.
Revealing mistake: Kirk uses a submachine-gun to shoot the lock of the cell holding Spock and McCoy, but no bullet holes appear, nor is the lock damaged.
Revealing mistake: A Roman guard empties half a magazine of bullets from his submachine-gun into Flavius, but there are no bullet holes in his body, nor blood on the floor from the wounds inflicted by the bullets.
Visible crew/equipment: Set lights are reflected in Spock's tricorder screen before he closes the cover.
Revealing mistake: McCoy is knelt down with the rather comically named Flavious Maximus attacking him. On the remastered version it is obvious it is a stunt double doing the part. (00:34:20)
Revealing mistake: After Kirk and party are captured by the police, a montage of scenes depicting the planet's buildings plays while the log entry is heard. One of the buildings shown, though hard to read, has the title "Massachusetts Institute of Technology" (M.I.T.) above the columns.
Character mistake: Spock expresses amazement that the natives of this planet speak Earth English, however, he and Kirk were both on the bridge when Uhura tapped into the planet's news broadcast and already know that they speak Earth English, and there's no reason to tell McCoy, because he heard it too. Commenting on it would be illogical. (00:07:00)
Answer: After causing Norman to overload, all of the other androids shut down. The same could be said for the androids on the Enterprise.