When John and Don decide to leave the ship after it has landed in the space probe, they are on the upper deck. They go through the doorway to the left of the ladder and elevator, and around behind them. In the next shot they come out on the lower deck from behind the elevator on the right. Obviously they didn't use either the elevator or the ladder, so how many different ways are there to go between the decks?
When Dr. Smith opens the door to the Space Pod bay, the door goes straight up into the ceiling. But there shouldn't be anywhere for the door to go, since they are on the upper deck of the ship.
The events of this episode take place on Saturday, October 17, 1947. However, that date was a Friday, not a Saturday.
Trivia: Dr. Smith's mother's maiden name is Ruthven.
Trivia: This episode carries the message that appearances can be deceiving. The ugly alien turns out to be good, while the one who glitters in gold, and appears charming, turns out to be ugly and evil.
Goof: After Smith takes pictures of the Jupiter 2 crew, and is back at Sesmar's lab, Sesmar comes to the conclusion that Don's emotion card is worthless and he throws it away. When Sesmar walks forward, the card is on the floor, but after he walks by it it is no longer there.
Don says that the Jupiter Two is passing Uranus and Arcturus. One is a planet in the Solar System, the other is a star over 36.7 light years away. They are nowhere close enough to pass simultaneously.
Trivia: Nerim is an anagram for "miner" - the occupation of Nerim.
Goof: When Dr. Smith meekly ushers Quano's father toward the Robinson camp, actor Michael Ansara turns his back to the camera and you can clearly see the skull cap he is wearing.
A.P. Tucker is heard calling Will Robinson "Bill". This is the only time in the entire series where that happens.
Trivia: The book that Penny is reading is Nancy Drew #19, The Quest of the Missing Map. Some of the details on the back of the book are covered over.
The phrase "Oh the pain...the pain..." is uttered for the first time in this episode and will go on to become Dr. Smith's signature line.
Smith sends the Robot off to warn the Robinsons after it has been stated by the Robot that the outside temperature is well above freezing. But, when the Robot is shown traveling toward the Robinsons, he appears to be walking over the frozen inland sea.
Don and John are walking outside in the apparent freezing cold on this planet. While having to hide from the giant cyclops, it apparently wasn't very cold in the studio where they filmed the scene, as a closeup of the two actors in their heavy winter clothing reveals beads of sweat on their faces.
First appearance of the "Chariot" vehicle.
First appearance of Penny's "space monkey" pet, Debbie. The animal appeared briefly in the unaired pilot, but this was its first appearance in the series.
The comet is shown to radiate light and heat. Comets are balls of ice that do not radiate heat, and only reflect light if there is a star in the vicinity.
When Will, Penny, and Judy look out the porthole at their parents, Will is standing in the front. However, when the camera cuts to a shot from behind, Will is in the back.
Despite the fact that John informs Smith that he will be treated as a stowaway, and suspects he tried to kill them, he gives Smith a gun when they leave the ship.
When John uses his gun to burn through the wall, there is no beam. When he turns to shoot at the aliens, there is a beam. Also, the wall continues to burn even after John stops firing and goes into the ship.