Message from Space is a 1978 Japanese science fiction film (starring Vic Morrow, Sonny Chiba, Philip Casnoff and Peggy Lee Brennan) about the peaceful planet of Jillucia and its attempts to freee temselves from the conquering warriors of the Gavanas Empire, who have turned the planet into a military fortress. Like you do.
Adding insult to the injury of being released the year after Star Wars, the special effects in Message from Space are laughable even by early 1970 standards. Gloriously so.
So, to sum up: you bring the popcorn, we’ll provide the cheese!