Features the first occurrence of the Robot's laughter, about which he says it is "only [his] computers being cleared" when Dr Smith asks what else "do we have to do" for work.
While both Will and Quano are said to be twelve years old, at the time of the initial airing of this episode Bill Mumy had just turned twelve, but Kurt Russell was fourteen and would turn fifteen two weeks later. Kurt is obviously significantly larger than Bill.
This episode has the first occurrence of Dr. Smith calling the robot a "bubble-headed booby".
Part of the costume for the creature in the cave that Quano challenges is obviously the head from 20th Century Fox's earlier The Fly (1958).
During the climatic battle Prof. Robinson is forced to fight in a sword duel. Guy Williams was a skilled swordsman who played the title character of Zorro (1957).