This was a thoughtful sci-fi story.
Bruce Dern appears as a bit of a deranged scientist in what may be his most likable role ever, which says a lot about the roles he has played.
He is a caring scientist, except he kills all his companions in a spacecraft. Well, can he still be likable?
He has a motivation for doing this which is more than the motivation for his other villains.
Here, he means to save plant life for Earth. His companions didn't even understand the need to save plant life, which tells you about the horrible times they live in.
All this happens fairly early in the film. Afterwards, his companions are robots whom he empathizes with as if they are human beings.
Earth has decided to destroy all plant life, so in essence, he plays a hero/villain, hard to tell. But does he manage to salvage something for humanity?