When Nomad is supposedly emerging from sickbay after attacking Chapel to see Kirk's records, he is instead seen emerging from the Turbolift.
When the security team is escorting Nomad back to the holding area, he goes his own way. As one of the security crewmen orders him to stop, he begins to reach for his phaser. But in the next camera angle, he already has his phaser out and trained on Nomad.
In the final scene on the bridge there is a blonde communications officer sitting at her station in the wider shot. As the scene cuts back and forth between close-ups of Captain Kirk and the wider shots, there is nobody sitting at the communications station in the close-ups, yet there is in the wider shots.
(at around 30 mins) When the Sick Bay doors open and Nomad comes out after reading Captain Kirk's medical file, his antenna is extended, but in the next shot when he enters the hallway it's retracted.
After Nomad has scanned Scott's medical data on the bridge at Spock's station, McCoy leads the probe to the turbolift, passing Uhura's station, where the chair is missing. A few seconds later, the chair is back at the communications station.
When Nomad is firing at the Enterprise, Spock states that Nomad is 90,000 kilometers away, and that the energy bolts are moving at warp 15. At that distance, even if they were moving at warp 1, their impact would be virtually instantaneous.
When Spock, Kirk and McCoy view a diagram that shows the various parts of the NOMAD probe, the lower right of the diagram contains the annotation: "Computer Data Banks Recall & Transmition," should read "Transmission". Additionally, "Magnetohydodynamic" should read "Magnetohydrodynamic", and "Sperographic" should read "Spherographic"
Uhura's memory is erased, her mind emptied and left blank, yet she is trained to read up to a first grade level and converse in Swahili in about an hour. But all of her memories before this moment would be gone forever and, since people's personalities are the sum of the experiences they have lived, she would, in reality, NOT be the same Uhura even if she was brought up to speed on training, language etc. This would have affected her character for the rest of the series as well as the 6 feature films. No attempt is made to explain her remarkably rapid progress, but, since it is also never thoroughly explained what exactly Nomad did to her, it is anyone's speculation as to how quickly she could recover.
When the Enterprise first encounters Nomad, the Enterprise fires back with a photon torpedo, after several hits from Nomad. The torpedo hits and explodes, and the entire bridge crew reacts to the explosion's light and sound effect.
However, in the next set of lines, Spock reveals that the object (Nomad) absorbed the full energy of the torpedo. If the full energy was absorbed, what was the explosion of sound and light?
However, in the next set of lines, Spock reveals that the object (Nomad) absorbed the full energy of the torpedo. If the full energy was absorbed, what was the explosion of sound and light?
Nomad attacks the Enterprise at range with what Spock describes as "a bolt of energy." As a straight-line attack, the Enterprise could have easily avoided it by moving laterally instead of straight back.
During Nomad's initial attack on the Enterprise, the bridge crew react to the "hit" so violently that the helm/navigation console is lifted clear off the ground and almost tipped over.
A wire suspending the Nomad probe is visible in numerous scenes (namely, at 23:30 when Nomad hovers over to Spock's computer to read up on human anatomy, and at 28:20 in the brig before Spock performs a mind-meld).
When Nomad breaks out of the brig and two security crewmen fire their phasers at him, the crewman on the left assumes an expression of shock and pain several seconds before Nomad fires back at them. There is no reason for him to do this prior to Nomad's attack, and the crewman at the right times his reactions correctly.
The overlong scenes of Spock mind melding with Nomad is to pad the episode's run time.
Nomad's initial attack, according to Spock, was equivalent to 90 photon torpedoes, yet caused no damage other than weakening Enterprise's shields by 20%. At no other point in the entire series has the Enterprise been so resistant to attack, suffering far worse damage from lesser attacks sustained by the Klingons, Romulans, Orions, and others.
When Spock mind melds with Nomad, Nomad would acquire Spock's knowledge of Kirk's true identity. Spock would acquire at least some of Nomad's knowledge of warp 15 weapons, warp drive improvements and medical technology.
Uhura had to be retrained in the ability to communicate, including the ability to read and speak. The scene in Sickbay shows her struggling with English, but somehow, she is able to speak perfectly good Swahili WITHOUT any training. She would need training for any language. This is a misconception, as people with memory loss (eg. Korsakoff syndrome, amnesia, grand mal seizure) will very often forget second (or possible even higher languages) even if they have been speaking their second language for decades and not muttered a word of their native language in said decades, and will revert back to their native language.
The crew is often thrown about the ship in battle or confrontations with aliens, yet nobody thought to install seat-belts on the ship's chairs.
Nomad, when confronted with its own error, should have recognized its own flaw with lightning computer speed and destroyed itself while still in Engineering (thereby taking Kirk and the whole Enterprise with itself), rather than conveniently trying to reason out (incredibly slowly, by computer standards) whether it was faulty or not.
In the brig's top security cell where Spock is going to mind-meld with Nomad, the shadow of a boom mic can be seen on the wall, upper left corner of the screen, at the 28:20 mark.
In the last scene on the bridge, Kirk is cracking jokes about Nomad in a light-hearted manner, which is not in keeping with the situation. 4 or 5 crewmen have been killed, and billions are dead in the Melurian system.
Spock states that the Enterprise's shields absorbed the equivalent of 90 photon torpedoes worth of energy. Yet when Nomad absorbs 1 photon torpedo of energy, Kirk acts genuinely astonished and asks if Spock's sensor equipment is damaged. Why would he be that amazed, if his ship just absorbed 90x that amount of energy?