The opening theme, especially the string section at the end...
TAC's theme. An instrumental is frequently heard, but a vocal version was sung by TAC after Minami left.
Bizet's Toreador Song from Episode 10
Debussy's Clair de Lune.
Once again, "Fight! Ultra Seven", heard when Ace destroyed Ace Killer with the Space Q.
Big-Lipped Alligator Moment: Muruchi's brief and sudden appearance to help Doragory and Metron Jr. in the Episodes 7-8 two-parter. and then for some reason that only makes sense to Doragory, he murders Muruchi in the most brutal death of the entire Ultra Series and then the fight resumes like nothing happened.
Cerebus Rollercoaster: The first half of the series is fairly dark for the most part, but afterwards, it gets a lot more inconsistent, with extremely zany episodes being interspersed with some more in tone with the early half.
Fair for Its Day: Tsuburaya Productions wrote the Ultras with no concept of gender inequality, thus the reason both a male and female host were chosen. However '70s audiences couldn't handle this, especially the kids.
Mikawa can be put on the same boat as Minami in that regard. Her debut made TAC the first team to have more than one female member, and she was the second-in-command of the team as well.
Fridge Brilliance: Many fans are still confused about the unexpectedness of Muruchi's appearance in a puff of smoke to help Doragory and Metron Jr. Cut to Ultraman Mebius 30-something years later, which reveals that Yapool has a smoke-like Choju named Gadiba able to take the form of non-Choju monsters. Hmmm.....
Narm: Jumbo King is not very scary, creepy, or well made. And this was the last of Ace's Choju.
The show has a lot of other ridiculous-looking Choju, but the absolute crowner would have to be Geegon, a violin kaiju, from the penultimate episode.
Seasonal Rot: The second half of the series (after Episode 28) is considered to be not as good as the first half, especially since the introduction of Dan Umezu was a painfully obvious attempt of aping Goh and Jiro's relationship in Return of Ultraman, ultimately proving to be unsuccessful as Dan vanished from the series after Episode 43.
Special Effects Failure: There's a downgrade of quality in the suit department compared to its predecessors due to Japan's declining 70s economy. Episode 40 (the one with Alien Steal) should receive particular note for featuring a panda obviously played by a man in a laughably bad costume.
What Do You Mean, It's for Kids?: There's a surprising amount of monster gore in the show. Episode 8 is an especially good example, with Muruchi's infamously violent dismemberment, Alien Metron Jr.'s guts spilling out of his sliced-open body, and Doragory having a hole punched through his stomach before being decapitated.