If you loved Invasion of the Neptune Men, try Gamera gegen Gaos - Frankensteins Kampf der Ungeheuer
Eine Brücke zwischen einem Film, den du schon gesehen hast, und einem, den kaum jemand kennt. Das teilen sie, und was der zweite macht, was der erste nicht macht.

Invasion of the Neptune Men

Gamera gegen Gaos - Frankensteins Kampf der Ungeheuer
Was sie teilen
Theysit in Action / Adventure / Science Fiction territory. If that's the register that drew you to Invasion of the Neptune Men, the second film will land in a comparable space — through a different lens.
What Gamera gegen Gaos - Frankensteins Kampf der Ungeheuer is
Lava-slick twilight, the first bat-winged shadow cleaves the thermal column. A shrike-like screech splits the sky as Gyaos begins its razor gust, travelers halved before flight bags land. An orphaned boy alone in a bunker feeds Gamera jelly sandwiches until the giant turtle trundles forth. Earth rumbles as the last creature who likes humans lumbers toward a daylight stand-off. A child’s lonely alliance against extinction, told in the shonky lexicon of Toho’s late-sixties kaiju.