17. Take Shelter
Okay, another movie many would not classify as horror, but for me, what is more horrifying than having to choose between accepting your mental health is slowly disintegrating and acknowledging the possibility the world might be approaching apocalypse? Add to that an incredible performance by Michael Shannon, more than ably supported by the lovely Jessica Chastain, an eerie and haunting score, and atmosphere to spare—loveliness, loneliness, and dread braiding like the skeins of birds that dance in these bleak midwestern skies—and I've just talked myself into watching it again. These are ordinary blue collar people we can relate to, an important aspect of why this film is so effective. For that and more, Jeff Nichols is someone else to keep an eye on; his direction lends this film a powerful sense of quiet unease worthy of Lynch while splicing it seamlessly with a Malick-like lyricism. Given my own tastes, and everything mentioned above, that combination is damn near unassailable. I'm already regretting having this too low on my list.
18. Kill List
Ah, England again. Ben Wheatley: watch out for him. There's little I can say that won't spoil it, so yeah, just find this gem and watch it. Unflinching is a word that leaps to mind. Unpredictable, too. Really, like many films on my list it's a hybrid—a pagan horror mystery thriller road movie. Yeah, just watch it. Be warned, though: it doesn't pull its punches. Thoughtfully brutal.
19. Alien
In light of my last choice, highly predictable, no doubt. But still. Pretty much everything I said about The Thing applies equally here. If anything, it's even more claustrophobic, has a slightly more iconic gross-out moment, asks questions about artificial intelligence many straightforward sci-fi films often flub, and there's a little more Yin to The Thing's Yang. As in Sigourney. Yes, it's hardly original of me, but I compare the two films in the darkened movie theatre of my head often enough for it to be unhealthy, and I love them both, and perhaps because it came first I rate Alien a tiny notch higher. As great as the XY ensemble in a whiteout was, the extra X in a black void just edges it. Oh, did I forget to tell you how goddamn terrifying it is? In space, no one... etc.
20. The Thing
John Carpenter's version, from 1982. Once again, the borders are blurry, but whether this is sci-fi, horror, or horror/sci-fi doesn't really matter when you sit down to watch it and realise far too late you're trapped in scary-as-hell world, except it's not hell, unless hell froze over, because this is Antarctica and your choice is: stay and fight (or hide from) whatever appallingly wrong thing has invaded your camp and taken over your friends' bodies or walk out into the ice and die. This film is relentless. And beyond the relentlessness, there's a purity, too. Just watch the clip. It's an incredible opening scene. Gorgeous, expansive, somehow lonely. But after this, everything closes in and becomes chillingly, hermetically sealed. (Highest resolution and full screen recommended.)