After becoming smaller, Lieutenant Arex mentions that his eyes no longer reach his station's opticals, but the navigator station has no opticals.
If the space between the atoms is reduced but the weight of the shrunken objects remain the same, the crew would soon find it hard to move under their own weight. To say nothing of what would happen to the ship to beam aboard an entire city of perhaps diminutive size but gargantuan weight.
The crew somewhat confusingly alternates between using metric measurements ("1 centimeter high") and imperial ("we are going down to 1/16th of an inch high").
Spock notes that the coral in the aquarium is shrinking along with them. However, as he states that, the shot shows the coral coming up to his neck. The aquarium was not large enough to hold coral that big in previous shots.
When Chapel recovers the miniature laser, it is a solid disk. It is still a solid disk when she walks along the shelf and trips. However, when she falls into the aquarium, it is a torus. When she gets out of the aquarium, it is solid but with an inscribed circular line in the center.
In one shot the elevator doors are light gray rather than their usual color.
Just after discussion how DNA is another substance that contracts, Spock turns away to do his calculations and his badge is gone, then flickers back in as he completes his turn.
Just as he prepares to beam down, Kirk describes the spiroid rays as "lethal," but there's no indication that they are, before or after.
It's stated that the bridge crew are beamed away. However, Nurse Chapel is one of the people taken, and she's not bridge crew and given the number of ship's emergency medical situations, is unlikely to have been on the bridge. Also, there are several other people seen on the bridge later who aren't taken as part of the "bridge crew."
As established, when the transporter beams someone down, it immediately restores them to normal size. However, when the Mendent tells Gabler and three other unidentified crewmen that their city is close to destruction, the Enterprise crewmen are still at their miniaturized height. If they had beamed down from the Enterprise, they would be at their normal height.
When Kirk goes to the transporter room to inspect the Terratin city, the macroscope he uses is pointing at an angle toward the floor. However, when he looks through it at the Terratins, the view is if he were at ground level with them.
Kirk: Spock, are you slumping?
Spock: I have never slumped in my life, Captain.
Mendent: I do not know how to beg. I can only request. Save as many of my people as you can.
Mendent: We name you honorary Terratins now and for all time to come.
Spock: We came rather close to making it more than honorary.
Kirk: Yes. I'd say about a 16th of an inch close.
Author Paul Schneider scripted the original Trek episodes "Balance of Terror" and "The Squire of Gothos."
Kirk: The Lilliputian city is to be taken to Verdanis.
The Terratin city is referred to as lilliputian. Gulliver's Travels, written by Irish clergyman Jonathan Swift and published in 1726, is a collection of the experiences of sea captain Lemuel Gulliver. Gulliver explorered a number of fascinating places; each journey carried a measure of social commentary. One journey carried Gulliver to the land of Lilliput, whose inhabitants were just a few inches tall. The word lilliputian came into the English language from this tale; although there was more to the tale than just the small of the inhabitants.