When the alien ship's bridge starts to explode, Kirk and the others are lying on the ground. When they materialize back on board the Enterprise they are standing up.
When the landing party beams over to the alien ship, in a number of shots the yellow force field "outline" is badly off-center, with gaps on the left or right and an overlap on the character body on the opposite side.
Kirk tells Sulu to use the "mutual override" to regain control of the ship. The term he should use is "manual override."
Arex is shown seated at the navigator position next to Sulu for the most part, but in several shots a brunette red-shirt is seated in the position instead, before the camera cuts back and Arex is there again.
When Kirk orders the forward scanners on to see the dead star, the viewscreen "whooshes" and slides open vertically, as if there is a shutter over it. It is not a shuttered window.
Uhura: It's beautiful. What kind of people could have built it? To touch even a starship with grace and beauty?
Kirk: A civilization that advanced 300 million years ago before life even emerged on Earth.
McCoy: Barely an instant in eternity, Jim.
McCoy: Gives me the creeps. I feel like something's watching us.
Scotty: I feel it too, Captain.
Spock: A physiological symptom of latent primal superstition, the fear of primitive people confronting something unknown to them.
Kirk: Compared to the beings that built this ship, we are primitive people, even you, Mr. Spock.
Scotty: But nothing, no form of life could survive 300 million years.
Spock: Quite right, Mr. Scott. No known form of life.
This episode along with "Yesteryear" was released on The Animated Adventures of Gene Roddenberry's Star Trek: Volume 2 for VHS.
Majel Barrett is credited but her voice talents aren't employed.
Author Samuel Peeples scripted the first Kirk episode of Star Trek and the second pilot: "Where No Man Has Gone Before."A
For the first and last time we see the bridge's 360 degree security/phaser system, which promptly is used by the alien to attack the crew.
This episode takes advantage of the benefits of animation to replace the clunky life-support suits from the original series with force field belts. Of course, actually it was a cost-cutting measure: the artists could simply use regular shots of the crew and put a yellow light around them, instead of drawing new animation of life-support suits!
They couldn't get John Winston to do the voice of his character Kyle from the original series, so they got the ubiquitous James Doohan to do it.
Editor's note: Most official sources claim this was aired 14th, on 12/22/1973. However, I saw this episode on 9/8/1973 and the most comprehensive site I can find, Curt Danhauser's Guide confirms this. And note that Alan Dean Foster novelized BtFS first, Yesteryear second, and One of Our Planets is Missing (the second episode in "official" air order) third. All contained within Star Trek Log One. So this episode reflects the accurate airing of episodes, despite what most other sources say. According to one contributor, Jmodene, the episode did not air in the primary Los Angeles market because George Takei was running for City Councilman and his opponents demanded equal time if this episode aired, so it wasn't aired there. However, such a localized pre-emption, even when the locality is Los Angeles, should not cause such a widespread error. Furthermore, in the East NBC aired live sports coverage shortly after their "kidvid" block, which would not have been subject to the standard three-hour delay in the West as the children's line-up would have been, causing its later programs to be pre-empted on all Pacific time zone affiliates.