Godzilla vs. Gigan (1972)

The twelfth movie has a theme park (under construction) with a life-size Godzilla Tower, which naturally doubles as a base for villainy. The builders are on a quest to bring "absolute peace" to the entire planet, but as with many things in life the exact meaning of such a politically loaded phrase is open to interpretation. A manga creator named Gengo (Hiroshi Ishikawa) stumbles into the evildoers' plot, aided by a duo of resourceful Japanese hippies.
The real Godzilla, meanwhile, is chilling on Monster Island, chatting to one-time foe Anguirus via actual speech bubbles - I shit you not. When they learn that the mainland is threatened, the kaijū decide to lend the humans a hand.
As you can see from the original poster art, it's not a one-on-one battle with the cyclopean invader. But before the battle, the plot pauses in order to deliver a message about the dangers of an over-reliance on technology.

2½ image projections out of 5