Gappa the Triphibian Monsters

I was visiting this movie approximately in 1972, when communist allow us to see two or three Japanese "sci-fi" movies. In that time it has been for me something new, I've been a small boy, but I feel it is not good. But it has been from my lovely sci-fi section and now I bought a DVD and look at it with pleasure. There is so much mistakes... For example the rocket propulsion of that giant lizards, the fire from their mouths when they destroyed all military technology - tanks and aircraft, their bullet, bomb and rocket proof skin. The monsters can fly, walk and float under see, just one problem they have - they don't like high-frequency sound, so army can thrust their from the lake under Fuji. On the island, where from are the monsters are living the natives which are waiting tens generations for Japanese liberators, but almost all know the Japanese language! The end is beautiful and very sentimental - first and last time you can see a giant monster to cry:-)