In the opening fight scene, Kirk's position changes on the bench between cuts.
The collars of obedience show the colors of the 3 Providers to be red, yellow, and blue. When Kirk is transported to the Providers, their colors are red, yellow, and green.
During his final conversation with Shahna, Kirk's hair changes position between shots.
When Kirk and Kloog get into a one-on-one fight in the combat area, Kloog holds a whip. He drops the whip near Shahna when Kirk jumps on him. When Kirk is victorious, the whip moves further into the ring and away from Shahna. Soon after that, the whip disappears entirely with no one holding it.
When Kirk starts telling Shahna about Earth, his face is right next to her hair, but in the close-up of Shahna, her hair is next to Kirk's shoulder.
Kirk, Chekov and Uhura are supposed to be beaming down to Gamma II but they are not wearing spacesuits. Gamma II is revealed on the screen to be a barren world pockmarked by meteor craters, similar to Earth's moon, and Spock says there is no sign of life there. Kirk and the other two could not possibly survive without protection.
In the fight with the Andorian, when Kirk's back is to the camera his collar comes loose, opens and falls off. The scene instantly switches to him on top of the Andorian and his collar is back on.
In Kirk's fight with the Andorian, his rubber knife waggles back and forth.
When Kirk, Uhura and Chekov first attempt to fire their phasers, the small light at the tip is visible in a close-up. This light in the prop is worked by the trigger and is there to synchronize the firing of the phasers with the special effects added in post-production.
Obvious stunt double for Captain Kirk in the whipping scene.
The Andorian thrall's hands are those of a Caucasian man whereas they should be blue.
The Triskelion badge/logo on Galt's chest is reversed.
Provider 3 (the green one) says "Not for true gamesters, Captain" but the voice of Provider 2 (the yellow one) is heard.
At 8:55 Kirk, Uhura, and Chekov fall to the ground writhing in agony. The Steadicam operator moves in for a close-up of Chekov and captures a piece of camera equipment sitting on the floor. He quickly pans to the right.
In addition to Kirk and the Thralls stepping on each other's colors in the contest without being penalized, Shahna is allowed to submit and give up when the fights are supposed to be "to the death".
Despite the instructions for Captain Kirk to stay in the yellow/gold areas in the final fight, he steps in the blue areas with no consequence.
When the drill thrall brings Chekov his meal in his cell, every time the camera focuses on Chekov sitting on the bench, the shadow of the boom mic can be seen hovering on the wall behind him, just above his head.
At the end of the story, when Kirk moves in for his last kiss with Shana, the camera moves in from behind Kirk. The shadow of the mic's boom moves across Kirk's back.
Galt tells the landing party that their old titles are meaningless here, yet he continues to refer to Kirk as "Captain".
As Lars is taking liberties with Uhura, Kirk shouts "What's happening to Lieutenant You-hear-uh?"
When the landing party has been promoted to full-fledged thralls, Galt states that further disobedience will be punished by death. When Galt catches the party trying to escape later, he only briefly chokes them.
Kirk asks Shahna about her birthplace, and Shahna seems confused by the concept of being born. Kirk asks her after that about her parents, and Shahna talks about "She who bore me."