At issue here are two problems: first, I had never seen the series in its entirety before, in order; two, I have no idea how much of the story was changed for the Americanized version.
Episodes 1-24 dealt with their trip from Earth to Iscandar.
Ep 25 dealt with their arrival on and (brief) exploration of Iscandar, after which they left. Ep 26 dealt with the trip home, which was naturally almost entirely unhindered by the Gammilons and Leader Desslock/Dessler--but not completely unhindered.
I was disappointed that there was no denouement: we see them arrive at Earth; and the series ends right there. During the end credits the Earth turns into a big blue marble again as the "Cosmo Cleaner D" is apparently switched on.
It would have been nice to see the restored Earth and the characters' actions thereon. They also left open the question of Captain Okita's disposition: did he in fact die at the end of the series, or did he live? And if he did live, couldn't they have had his funeral on the restored Earth as part of some kind of denouement?
I then watched ep 1 of the second series, "Comet Empire". (SB:CE)
I am realizing how much influence this story has had on my own science fiction. Then again, when I was 12 and starting junior high school, that was about the time I chose to begin writing fiction for fun; and as I liked SF I chose to write SF...and 1979 was when SB was being broadcast here in the Chicago area, early in the morning on one of the UHF channels. (44, I think, but don't quote me.) Many was the school day that I woke up to SB on the TV, let me tell you.
Fortunately, the influences I got from SB:CE are not incompatible with what I have subsequently learned and/or formulated about the operation of deep space combat vessels. SB as a series suffers from some serious issues with what can be crammed into the volume of the Yamato as built by Japan in WW2--and as we see in the earliest eps of SB, the space battleship Yamato has exactly the same dimensions as the wet navy battleship--but though the series plays fast and loose with the science at times, it gets a lot of the military bits right, particularly when it comes to large ships carrying fightercraft. IMHO the plots of the battle sequences would not be out of place in more modern SF.
I'm looking forward to watching more of SB:CE.