During episode 13, a mysterious red mobile suit can be seen in Hayato's museum. It is altered version of Walker Galia, the second protagonist mech from Combat Mecha Xabungle, another Sunrise's mecha anime directed by Yoshiyuki Tomino.
First "Gundam" series to include the concept of transformable mobile suits.
Zeta Gundam brought a lot of firsts to the gundam franchise. It was the first to include more than one MS with the gundam name. It introduced the concept of the lead character receiving a more advanced gundam and giving there gundam to another character. It introduced the concept of both sides of the conflict operating gundams. The series also introduced Transforming MS bringing the gundam franchise in to the 80's
Apparently, the mecha design of the Zeta Gundam itself was a competition among the series designers, with Kazumi Fujita eventually winning the competition, leading to his distinctive Zeta Gundam being animated. However, rejected designs for the Zeta Gundam were animated once they were reworked, examples being the MSN-00100 Hyaku Shiki and the MRX-009 Psyco Gundam.
The melodies of the TV series' two opening themes and sole ending theme were written by American pop singer/songwriter Neil Sedaka. "Zeta - Toki wo Koete" was based upon the song "Better Days are Coming" from Sedaka's 1972 album 'Solitaire,' while "Hoshizora no Believe" was adapted from the song "Bad and Beautiful" from the 1976 album 'Steppin' Out.' Additionally, "Mizu no Hoshi e Ai wo Komete" was derived from an unreleased song entitled "For Us to Decide". Due to this fact the US DVD release had to replace the op/ed music with BGM songs since Bandai did not own the right to distribute the music outside Japan.