A very dramatic episode which heralds the more adventurous character of the 3rd. season. Exciting scenes throughout, beginning with the explosion inside the Jupiter 2, the scenes with Will and Dr. Smith entering the Robot, and the final dramatic exit from the Robot. A few of the soundtracks used more frequently in 3rd. season episodes are heard during the climax of this episode.
In a season marked by many \\\"kidsy\\\" episodes, this episode brings the series back to a more serious mood. The audience is reminded of the alien, hostile nature of the planet with \\\"The Valley of Shadows\\\" and the Robot\\\'s recorded message sharing his awareness of the \\\"brave struggle you have made to survive on this planet.\\\" The music played when Dr. Smith and Will search for the Robot is captivating, recalling the music used in the earlier 2nd. season episode \\\"The Ghost Planet\\\" and \\\"Forbidden World\\\".
The sound effects inside the Robot are fascinating also. The sound effect of the Robot\\\'s diode timer is the same used in the 3rd. season ( in \\\'Kidnapped in Space\\\' when the Xenian robot leader communicates; in \\\'Space Destructors\\\' when the cyborg creating machine\\\'s conveyor tube has created another cyborg). The approach of the infrared heat seeking laser unit is a dramatic moment, even with the silly red light on top of the apparatus. This is truly one episode in which Dr. Smith is getting into one trouble spot after another! The scene where he is on his back caught in the magnetic tube is a memorable Dr. Smith-in-trouble moment. Some things that are questionable: The Robot doesn\\\'t look quite as big on the outside as he does inside. On the outside, he only looks \\\'as big as a house.\\\' On the inside, he seems as big as a vast building complex. When Dr. Smith and Will find the Robot, it is probably around 4 in the morning. When John and Don finally find the Robot, it is already the following evening. Could that much time have elapsed since Dr. Smith and Will entered the Robot? Even as big as the Robot got, did it really take them an entire day to traverse the inside of the Robot? Also, why didn\\\'t the Robinsons think at first of using the chariot to recharge the Robot, instead of letting him go off into the wilderness as he did in this episode?