It's the fortieth anniversary of the release of Alien. In its honour, I'd like to try and breakdown why it's arguably the most effective horror movie ever movie. Much like how the xenomorph has different evolutionary forms, so too does horror
In the introduction to his short story collection Maps in a Mirror, Orson Scott Card identifies three stages of fear: 1) Dread 2) Terror and 3) Horror.
Dread is the first and strongest of the three kinds of fear. It is that tension, that waiting that comes when you know there is something to fear but you have not yet identified what it is... Terror only comes when you see the thing you're afraid of. The intruder is coming at you with a knife...There is a frenzy to this moment, a climactic power—but is the power of release, not the power of tension. And bad as it is, it is better than dread in this respect: Now, at least, you know the face of the thing you fear. You know its borders, its dimensions. You know what to expect. Horror is the weakest of all. After the fearful thing has happened, you see its remainder, its relics. The grisly, hacked-up corpse. Your emotions range from nausea to pity for the victim. And even your pity is tinged with revulsion and disgust; ultimately you reject the scene and deny its humanity; with repetition, horror loses its ability to move you and, to some degree, dehumanizes the victim and therefore dehumanizes you.
I agree %100 with pretty much every thing Card says here, especially with what he says about dread, and I think it's really interesting how it maps onto Alien. Much of the film's running time is committed to building that sense of dread. We learn about these characters, come to understand them and like them. Despite being astronauts out in the far reaches of space, we begin to see they're familiar to us. Most of them are actually working class, blue collar truckers in space, getting pushed around by their bosses.
Then they get a distress call to a strange planet. They investigate an even stranger craft filled with gigantic eggs. Something lashes out and attaches itself to a character's face. What is this alien creature? What is it doing to Kane? The sense of dread is nearing its peak. This is why Alien is often described as "Jaws in space."
And then the chestburster scene happens, when the xenomorph bursts (haha!) onto the scene. The tension is released (literally) in a moment of terror that has become one of the most iconic scenes in film history. But it doesn't stop there. The xenomorph continues to grow until it's seven feet tall, with two sets of teeth, and a tail like a scorpion.
From here on out, we're fully into the horror stage. Interestingly, Ridley Scott has described this third act of the film as "Texas Chainsaw Massacre in space." The fully-formed xenomorph stalks its prey inside the claustrophobic Nostromo, killing off the remaining characters until only Ripley--and Jones (always save the cat!)--are left.
In his intro, Card goes on to lament that too many writers fail to recognize the value of dread in horror. And I'm inclined to agree. Go read IT and see how Stephen King works to establish some kinda bond with every character before Pennywise kills them. By the time Georgie is pulled into the sewer, we have grown to love him.
None of the scares in Alien work like they do unless we care about these characters. James Cameron understood this when he made Aliens, probably the greatest sequel ever made. Watch how much time we spend with Ripley and the marines before they get slaughtered.
If you want those big pay off moments, you have to do the heavy lifting of establishing dread.