I distinctly remember taping this off of channel 11 back in the day. It's an treat for any kaiju fan, and has some of the best guys-in-monster suits combat ever filmed. It's also the rare film in the genre that portrays the Japanese authorities and army as having some level of competence, and actually mounting a well thought out and effective defense.??
It's pedigree is also somewhat odd.
That German title mentioning "Frankenstein"? It's because this film is one of the oddest sequels ever made. It's direct predecessor was "Frankenstein Conquers the World," an bizarre (though not as bizarre as this) flick that has to be one of the most deranged takes on Shelley's story ever created, involving heart of the original Frankenstein's monster being brought to Japan from Nazi Germany right as the bomb drops on Hiroshima(!). Oh, and that movie started life as a sequel to the original King Kong (!!!!). A real treat for any monster movie fan that's not to be missed.