There's a few answers to the above question but the only one that really matters is Night of the Living Dead. It's a movie that's been so influential and is so thoroughly familiar to horror fans that it's easy to take it for granted. But in rewatching it recently, I was struck by how well it still works. I mean, I didn't expect it to suddenly suck, of course, but I sure wouldn't have faulted it for not hitting me as hard as it once did.
But it did get to me. Besides being as scary as I'd remembered - it's a movie that's just relentless in piling on the horror - I was grateful to be reminded of how much real sadness the movie carries. It's not a traditional tearjerker, no, but the deaths in this movie aren't just there to be gawked at for the FX (like Capt. Rhodes' death in Day of the Dead) - they really pierce you.
When Judy (Judith Ridley) impulsively bolts out of the farmhouse to ride shotgun with Tom (Keith Wayne) on his run to the gas pumps, it seems like such a true gesture on her part. And when Cooper (Karl Hardman) slams the front door behind her, it already feels like the end has been written for her and Tom. After their mission to fuel up the truck has gone horribly wrong and Tom has bravely driven the flaming pick-up away from the gas pumps, when he turns back to help Judy free her caught jacket, it's still a jolt to see that truck explode. Romero doesn't milk the scene for any gratuitous suspense. We don't see a lot of fumbling with Judy's jacket - it's about being hit by that sudden, instantaneous loss of life.
That's the moment where Romero and co. really let the audience know they're playing for keeps. The early, unexpected loss of Johnny (Russell Streiner) was cause for concern but the abrupt loss of Judy and Tom in that one fiery moment moves the film to another level.
It's also interesting to watch NOTLD now and see how differently the zombies are depicted from how they went on to be portrayed in Romero's subsequent Dead films. Everyone who makes a zombie movie or writes a zombie book now always points to Romero's original Dead trilogy as the Bible in how to proceed (unless they're going off on their entirely own take) but it wasn't until Dawn of the Dead that Romero really started to refine the rules of what his zombies could and couldn't do. NOTLD is its own thing. You would never see a zombie stabbing someone with a garden trowel in a Romero, or a Romero-influenced, zombie movie today but yet it's such an iconic moment in the original when Karen (Kyra Schon) attacks her mother (I bet the main reason this scene was changed in the 1990 remake to Karen simply biting her mother - with the spurting blood splashing on a nearby trowel as a nod to the original - is because zombies weren't supposed to be capable of that kind of advanced action anymore).
There's also the crazed ferocity with which the Cemetery Zombie (Bill Hinzman) attacks Johnny and Barbra, to the point that he grabs a rock to smash the car window to get at Barbra. And look at Johnny's eyes when he returns as a zombie and sees Barbra:
The intensity that he looks at his sister with (can we call it recognition?) has subsequently became a violation of the rules (almost all zombies now have those murky cataract eyes that seem to see nothing). But it's such a chilling moment in NOTLD. The way that Johnny focuses his gaze on her, it's almost as if he's been trying to get to her ever since he came back. In NOTLD, zombies have the capacity to glare - a skill that's since been stolen from them. With Johnny's pale skin and glowering eyes, I also feel like there's a little hint of vampire lingering in this encounter - perhaps a faint spiritual residue from the acknowledged influence of Richard Matheson's novel I Am Legend.
While it's well-known that Romero imagined this film as the start of a larger story from the get-go, watching NOTLD I always get the impression that in the bigger world beyond the farmhouse things were generally well in hand. At one point, the field reporter asks the Sheriff if the problem is going to be wrapped up in the next 24 hours, or words to that effect, and the laconic Sheriff gives a pretty unconcerned response. From the perspective of law enforcement, this zombie plague seems more like a temporary inconvenience than an apocalypse. And that's something I always liked about NOTLD. Within that isolated, overwhelmed farmhouse, this is the end of the world but in reality it's a manageable crisis - nothing that a redneck posse can't successfully mop up once the sun is out. I feel like when that bonfire is lit at the end, normalcy - for what it's worth - has been restored.
Of course, I'm probably the only person who looks at NOTLD this way - because, you know, there's all those sequels that say otherwise - but I like the idea that all this really was just a wind passing through. It makes it seem a little sadder to me, and makes the character's losing struggles that much more bitter.
To think that these people might've survived their long night of horror only to become part of the thankless, never-ending fight against an army of the undead doesn't seem so poignant to me. But to look at Ben (Duane Jones) and Cooper's bodies next to each other on the pyre and think that they might've returned to their normal lives had they only found a way to protect each other and those around them for a few dark, desperate hours - well, that's something to mourn.