- Prop Recycling: Nearly every kaiju and alien that appears in this series was recycled from a suit that had been used in Ultraman Mebius, Ultraman Max, or Ultraman Nexus.
- The King Joe suit from Max was modified to create King Joe Black. The suit would later be given its original paint scheme in Ultraman Ginga S before finally removing the arm cannon in Ultraman X.
- Neronga's appearance in the first series was modified from the Max kaiju Geronga. The suit was then transformed into Magular for his appearance in NEO, much like the original Neronga costume.
- Aversion — Despite Gomora and Eleking suits being readily available from Max and Mebius, Tsuburaya opted to create new suits for Rei's monsters. The results were designs very similar to the original Gomora and Eleking compared to their Max and Mebius counterparts.
- Alien Zelan's appearance in Ultra Galaxy NEO was done by modifying the Alien Mates costume used in Mebius (somewhat ironic given that it was the other way around for the two aliens back in their debuts in Return of Ultraman).
- Role Reprise: This is Seizo Kato's final appearance in the Ultra Series as Alien Mephilas. He retired and passed away some time afterwards. Additionally, Takeshi Aono appears as Alien Zarab again.
- What Could Have Been: Eleking's role was originally meant for Gubila.
Trivia / Ultra Galaxy Mega Monster Battle