Invasion of Astro-Monster
怪獣大戦争 (original)
Starring Nick Adams, Akira Takarada, Keiko Sawai, Kumi Mizuno, Jun Tazaki, Akira Kubo, Yoshio Tsuchiya, Takamaru Sasaki, Gen Shimizu, Kenzô Tabu
It's a action & adventure and science-fiction movie, and has a rating of 6.2 out of 10 from Imdb which is usually fine for this kind of movie.
Watch it here
Not found streaming from Finland.