This first season was filmed entirely in black and white. The overall tone of this season was more straight sci-fi than that of subsequent seasons. There were some fantasy elements that crept in. In this season, Dr. Smith and the robot started out more as villains. The Robot quickly became more of a loveable character. Dr. Smith still was the villain, but instead of being cold, he became more comedicaly villainous. Instead of being vicious, he was just lazy, greedy, shiftless, untrustworthy, etc.The theme song for this season was composed by then relatively unknown composer by the name of Johnny Williams (later known as John Williams).
Because of direct competition with ABC's Batman TV series, this season was definitely the most campy of the three. The stories were more fantasy oriented than in the first season, with some of them being downright goofy.Dr. Smith was more over-the-top than in the first season. Many of the episodes featured Dr. Smith, Will and the robot, almost to the exclusion of everyone else.
Season 3 was somewhat of a new direction to Lost In Space. Several elements were changed. While the action in seasons 1 and 2 usually took place on the surface of some desolate planet, many of the 3rd season adventures took place in flight.Also, the show got a fresh look. the opening sequence was changed to a much more exciting set of graphics. the theme music for this season was composed by John Williams. It was much more upbeat and exciting. Also introduced in this season was a smaller spacecraft called the Spacepod. This element allowed some of the crew to remain on the main ship while others to go planet side.