Boring
I had to force myself to get through this movie, and I only did so because I'm a huge fan of science fiction. I got absolutely nothing out of this movie, it just wasn't all that entertaining.
Just because a film has a unique or complex plot, that doesn't necessarily make it a good film. I haven't read the short story this film is based on, but if it's as boring as the film then I think I'll pass.
In hindsight I'm actually not surprised I didn't enjoy this. I've tried delving into Heinlein books in the past but found them to be mostly a chore to read. Some of the themes and elements he makes up in his stories are fantastic, but his writing style can put anyone to sleep.