What is sci fi violence?

Answer 1

We just watched Prometheus which was rated R for sci-fi violence. We wondered what exactly the term meant as well, but think it perhaps has to do with the creatures or blood involved. Perhaps the violence not resulting in red blood is considered "sci-fi". Maybe it's that the violence is between aliens and humans (as opposed to human vs human). I'd love a better answer, but that's what we came up with.