I have finished watching the first season DVDs. I had not seen the season in its entirety since the early 70s when Lost in Space first went into syndication. I noticed many details that I hadn't noticed as a child, both because I was paying attention to the continuity and because I've read a lot about the series as an adult. I have some questions and comments.
In "No Place to Hide," the unaired pilot, Don is referred to as a doctor, although he's not a medical doctor. Judy, who is introduced as Judith, is 19, while Will is 9. Penny's age is never given, although she has a 140 IQ. It will take 98 years for the Robinsons' ship, the Gemini 12, to reach Alpha Centauri.
In "The Reluctant Stowaway," the pilot that aired, Maureen becomes ill, and she also becomes ill in "The Oasis."
Since Dr. Smith is now on the ship, he gets his own cabin. So who had to move out? Is Will bunking with Penny, or Penny bunking with Judy, or (doubtful because it's the 1960s) Judy bunking with Don? Or did Maureen and John have their own cabins, and they are now together? I'm not going to even begin to contemplate where Dr. Smith got his changes of clothes, much less his nightshirt....
The planet's odd orbit was something I didn't pay attention to as a child, and I didn't realize until watching the show again that the orbit remains a problem throughout the entire season. That continuity was unusual for the 1960s, and the writers are to be commended for doing it.
I always loved the music that is played when John or Don is flying with the jet pack. That music is heard nowhere else, which is unfortunate.
There were a number of abandoned underground civilizations in the first season, plus one that was just beginning. Were all these civilizations once associated with each other? With the exception of "The Lost Civilization," the artifacts all looked Egyptian or Hindu. TLC was clearly borrowed from the 1930 art deco style of Buck Rogers, and the majordomo sure looked like Ming the Merciless! Someone suggested on the IMDb that these various communities probably died because of the planet's erratic orbit.
This is just a fan fiction idea, but maybe the civilizations were all originally above ground, but then the orbit went haywire, so the people went underground, and later died out. The abandoned communities were shown in "There Were Giants in the Earth," "The Magic Mirror,"
The Lost Civilization" and "Follow the Leader," while "My Friend, Mr. Nobody" was about a new entity in a cave.
Other examples of continuity: In "There Were Giants," there was the giant Cyclops, while in "The Oasis," both Dr. Smith and Debby the Bloop ate fruit that temporarily made them huge. Perhaps the Cyclops was normal sized, and ate one of the mangos as well, which made him grow? There is also a giant egg in "Return from Outer Space" and a small lizard that becomes enormous in "The Keeper."
In "The Sky is Falling" there must be a missing scene at the end. After the silent family leaves, John tells Will that giving the boy antibiotics cured his cold. John also called them Taurons. But there is no scene showing the little boy get well, or us learning what planet the family is from. Also, the closing credits give the mother, father and boy names, but they are never mentioned as well.
In "Return from Outer Space," Will calls the planet Preplanis, but nowhere do you ever see anyone telling the Robinsons that is the planet's name. Yet in "The Sky Pirate" which aired later, Will doesn't know the planet's name.
The Robinsons have three encounters with Earthling travelers, Jimmy Hapgood, Alonzo P. Tucker and the unnamed dog. I've always assumed that the planet is not that far from Earth, since the family meets others who are from there, or have visited there. Will mentions in the unaired pilot that it might be Cerberus that they are on (I assume he means a planet orbiting Cerberus, not the star itself).
More continuity: In "The Keeper," all of the alien creatures from previous episodes show up in the zoo. In "The Space Croppers," Sybilla and her family cultivate the same giant plants that tried to eat Judy in an earlier episode. In "All That Glitters," Officer Bollux is also a Tauron, but he can talk.
Final details: Dr. Smith calls Penny "Penelope" in "The Magic Mirror." In "Return from Outer Space," although it is never mentioned, it is just before Christmas, as there is a tree in the Simms' house and there are decorations around town.