8. Have A Clear Central Character
This may sound like obvious advice, but you won't believe how many screenplays (produced and unproduced) slowly wrench their protagonists out of pole position over the course of the story. Why does it happen? Usually, because the writer accidentally creates another secondary character who they find more interesting than their original protagonist. In an attempt to stick with a character who (in most cases) is more "fun" to write, the protagonist gets lost in the background. And that kind of happens in
Prometheus, what with Dr. Elizabeth Shaw and David. But
Prometheus suffers throughout because Dr. Shaw isn't much of a protagonist to begin with. Firstly, she makes it extremely difficult to identify with her, which is certainly something that you want to incorporate in the realm of sci-fi movies. She is constantly forced into situations that she never resolves, and ends up playing a victim, regardless of her status as a supposed scientific genius. The writers obviously had more fun writing David, the android character, something which likely emerged as a result of his moral ambiguity. He eventually emerges as the central protagonist (or it feels as though he does, at least), because he's better driving the events of the story. Elizabeth, relatively passive, falls out of our favour and relative interest. This choppiness makes the screenplay feel at odds with itself: it's almost as if, having written it, nobody could be bothered to go back, and define the protagonist. The result is a movie that feels conflicted, because - as audience members - we're not sure who to feel comfortable with. When writing your own script (of the blockbuster variety, at least), try to ensure that movie-goers have a character they can identify as the main protagonist.