A very peculiar film. I'm surprised this one isn't better known among film fans, but the fact that it was never fully completed probably hindered its popularity. Zulawski's solution (adding narration and unfitting footage) isn't ideal either, but that doesn't take too much away from the talent on display.
The film is split in three different parts, focussing on astronauts who left Earth for a new place to live. The first chapter is about their arrival, the middle part about their integration with a different species and the final part offers a flashback that explains why they chose to leave Earth behind.
The fantasy/sci-fi elements are extremely well realized, the cinematography and performances are intense and the film clearly influenced a bunch of others (Oshii cited it as an influence on Avalon, I also felt The Land of Cards vibes from it). If Zulawski could have found a better way to complete it, it might have been a personal favorite, but definitely worth checking out.