Terror Of MechaGodzilla is the fifteenth and final Godzilla film in the showa era. The idea for the film was submitted from a story contest where it would continue where Godzilla vs MechaGodzilla left off. The original script would have had two dinosaurs that were called "The Titans" that would later transform into one super monster called Titanosaurus. The idea for "The Titans" were scrapped and decided to use the Titanosaurus part instead. Another change made from the original script was that the final battle was suppose to take place in Tokyo and end with Tokyo destroyed, but it was altered to where the battle would be moved to the countryside due to limited budget.
After MechaGodzilla was destroyed by Godzilla a search party was sent to recover the robot's remains to find that something else awaits them. With the help from Dr. Mafune and his daughter, Katsura, the aliens rebuild MechaGodzilla and join forces with Titanosaurus to continue their invasion and defeat their arch-nemesis, Godzilla.
As the final installment in the showa era, it was a nice send off for the king of the monsters. It wasn't a movie that made it obvious that it was the finale, but it is one that is highly favored. With Godzilla now being the one that was alone, it really puts Godzilla to the test of strength and endurance as he has to face two monsters instead of one.
Katsura's and Dr. Mafune's backstories are kind of sad and you can see the emotional regret from Dr. Mafune later in the movie. There is also this sub-plot where one of the Interpol agents and Katsura have this love affair, which makes this movie even more sad when the movie reveals that Katsura is not who he thinks she is. So the movie's story is sort of dark and it does a good job making me care more for the characters. It really wanted me to root for them through the end and to see them succeed.
If you liked Godzilla vs MechaGodzilla, Terror Of MechaGodzilla is right up your alley. It isn't your typical finale, but it ends on a high note like the previous Godzilla films. It is definitely another one that I recommend watching.