A volcanic eruption serves the dual purpose of calling Gamera and waking Gyaos, an ancient flying lizard-bat that shoots sonic beams. Nearby, a greedy firm is trying to build an expressway through a village of equally greedy people. The prepubescent grandson of the village elder is obsessed by Gamera and makes friends with him. It is up to the child, the expressway supervisor, and some scientists to stop Gyaos.
Following the lead of Godzilla films of the time, Gamera vs Gyaos aims for a younger audience. Giant monster movies tend to be aimed toward the young, but we are talking single digits here. Four to six-year-olds are the audience. Show this to a ten-year-old and he’ll be embarrassed. The monsters are now filmed to expose every weakness in the special effects and they are weak. The Gyaos costume is bargain-basement and Gamera doesn’t look any better. The attempts to place a human in the same frame as a monster—which comes up often as both monsters lift the child—come off as failed Styrofoam homecoming floats. But then this is a film where a kid rides on the giant turtle’s back and road inspectors and children can wonder into government briefings, so no one was terribly worried about not being embarrassing.
Gamera is a straight-up hero now—this change is never explained. He never harms people or property, and shows up just to stop Gyaos. He’s become a big puppy, listening to the call of his master, the Kenny. And that kid never shuts up. There are ten solid minutes of the child yelling “Gamera!”
With so much time spent with the Kenny, and in meetings, there’s no time for the characters (and no money for the cheap-ass fights). After the kid, the lead is probably supposed to be the road superintendent, but he gets to do nothing. They don’t even bother with the semi-romance with the Kenny’s sister (so why is she in the film?), but then romance doesn’t fit in a film for a sex-year-old.
It all ends in a peppy Gamera song, in case you needed a statement that this film is just a string of bad discussions.