Terror of Mechagodzilla

"Even if you're a cyborg, Katsura, I still love you!"

—Akira Ichinose

"What do your bullets matter? Hahaha!!!"

—Commander Mugan

The final film of the original series, also known as the Showa Era of the Godzilla series (while Destroy All Monsters is the last film chronologically), and directly taking place after the previous year's Godzilla vs. Mechagodzilla. This is the final Godzilla film directed by the legendary Ishiro Honda.

The Terror of Mechagodzilla was not well received when it was released, and Toho would not produce another Godzilla movie until the king's 30th anniversary in 1984. The film was one of only two Godzilla films to have less than a milliion tickets sold. It would remain the least attended Godzilla film until Godzilla vs. Megaguirus in 2000. This would also be the last Godzilla film to be directed by Ishiro Honda. The music was composed by Akira Ifukube, and the special effects were directed by Teruyoshi Nakano. The film was produced by Tomoyuki Tanaka.

Tropes used in Terror of Mechagodzilla include:

Arbitrary Skepticism: The scientists don't believe Mafune's theory of a dinosaur living near Japan despite the fact that two Godzillas had already come to Japan before doing such (The first was a villain while the other in 1955 had a Heel Face Turn, serving as Japan's protector).
Alien Invasion: Yep.
Armor Is Useless: Averted. Mechagodzilla is immune to pretty much everything under the sun, and takes multiple hits from Godzilla's atomic ray without slowing down. He's only destroyed after Katsura, who has Mechagodzilla's controls inside of her, kills herself.
Blow You Away: Titanosaurus can use his tail like a fan, easily knocking Godzilla off his feet.
Darker and Edgier: Compared to the previous film and the other two before it, TOMG is the darkest Godzilla film in the Showa series since Godzilla vs. Hedorah. Sure, it's not as dark as the first film, but there are definitely clouds hanging overhead. Mechagodzilla's paint scheme even seems to lampshade this, as it is a darker grey compared to the bright silver of the previous film.
Died in Your Arms Tonight: Katsura dies in Ichinose's arms after committing suicide.
Dynamic Entry: Take a wild guess.
Gentle Giant: Titanosaurus. He is only violent when he's being mind-controlled.
Giant Equals Invincible: Titanosaurus and Mechagodzilla are both pretty much immune to bullets and mortars. Titanosaurus is still vulnerable to sonic waves and Godzilla's atomic ray, after receiving multpile hits from it.
Heroic Sacrifice: After Ichinose refuses to kill her, Katsura takes the laser gun and shoots herself, destroying Mechagodzilla's controls.
Immune to Bullets: Mugan would like to believe this about himself, and he may be right, but he and his escape ships are definitely not immune to Godzilla's atomic ray.
Improbable Aiming Skills: Apparently, one of the humans who was aiming a sonic emitter onto Titansaurus somehow aim at his neck.
I Cannot Self-Terminate: Subverted. Katsura thinks that she can't, so she asks Ichinose to kill her. He refuses, so she takes the gun and destroys Mechagodzilla's controls herself.
It Only Works Once: Godzilla takes Mechagodzilla's head off like he did before, but this time Mechagodzilla has a backup head that can't be removed so easily. It can also shoot a laser.
Macross Missile Massacre: Mechagodzilla unleashes a torrent of lasers, rockets, and missiles at Tokyo and later Godzilla.
Mad Scientist's Beautiful Daughter: Katsura Mafune.
Mid-Season Upgrade: Mechagodzilla receives a backup head and...revolving hand missiles. Otherwise, he retains the same weapons and abilities he had in the previous film.
Naked on Revival: In the Japanese version at least. While reviving Katsura again, they show her breasts (unusual for a Godzilla film). Obviously, this is cut out in the English version so the film can obtain a G-rating. The scene in the Classic Media release.
No-Holds-Barred Beatdown: Titanosaurus and Mechagodzilla are absolutely brutal in their attack on Godzilla.
Spell My Name with an "S": Commander Mugan, Mugen, or Mugar, which is it?
Swimming Into The Sunset: The film ends as Godzilla returns to the ocean while the sun is setting.
They Called Me Mad: Dr. Mafune was ridiculed for his staunch belief that there was a dinosaur living underwater near Japan. Apparently, no one ever sought him out and apologized to him after a certain event in 1954. Sure, he was referring to a completely different dinosaur, but still.
- He also has apparently become mad as well, unfortunately.
Title Drop: A subtle one of one listens carefully:

Commander Mugan: "That's when we will counterattack Tokyo with Mechagodzilla!"

- If you listen carefully, he says "Mechagojira no gyakushu-da", which is the Japanese title of the film Mechagodzilla's Counterattack".
Tragic Monster: Titanosaurus. Constantly being used and forced to do things beyond his control, he is finally free at the end, only to face the wrath of a tired and bitter Godzilla, who didn't know about the mind control. Katsura can also count, to an extent.
Weaksauce Weakness: Titanosaurus is susceptible to sonic waves.
What Measure Is a Non-Human?: Katsura, being a cyborg, struggles with this throughout the film. It doesn't help that the Simians do their damnest to make her turn against humankind. Ichinose convinces her that she's still human because she can produce tears, and he says that even if she's a cyborg, he still loves her.
What the hell, heroes!?: The main humans weaken Titanosaurus with the sonic emitter to help Godzilla, despite knowing its' mind control. Then Godzilla ruthlessly kills Titanosaurus after the final battle, despite the fact that Titanosaurus was under said mind control the entire time.