NOTLD is a masterpiece, and I agree wholeheartedly. I wouldn't say everything since has been terrible, but I certainly can't think of counterexamples. I feel like the concept is rich enough to explore more than NOTLD did, so I feel like someone must have done it...But maybe you're right. The Thing might be my favorite horror movie. The blood testing scene alone is such a fucking masterclass in tension building, and I've always loved the sound-design of the thing screaming when they get it outdoors. Poltergeist is great, too. I have a hard time crediting Texas Chainsaw Massacre's success to Tobe Hooper's genius because of everything that came after, but I know I love the movie for what it is (even if he never managed to replicate the same feeling). I felt like the set design and camera work kept things feeling grounded...And the fact that the production was such a fucking nightmare to work on! Adding Tetsuo The Iron Man, Screamers, and The Black Hole to my list! I haven't seen Orfanato or The Devil's Backbone either, so I'll slide around to them eventually. I'll PM you if I ever work through the recommendations I've already collected!
I've gotten into some pretty deep, pretty intellectual discussions about zombie movies. As a screenwriter, there's a point where you feel like shitting out a zombie movie. Probably because zombies are so fun - they play right into our anxiety in crowds, our road rage while commuting, and our general displeasure with "humanity" as a gestalt, regardless of how we feel about humans. The thing is? "zombies" are basically Alzheimer's patients. They're slow, they're shambling, and they pose a physical threat only if there are a lot of them. So all of a sudden we have "running" zombies at which point it's basically just "fear of crowds". except they always have to be idiots, too. You can't write a zombie anything without it turning into "the zombies are handled, what shall we fight about for the other 2/3rds of the movie" because as movie antagonists go the only adversary worse than zombies is trees (lookin' at you, M Night). Best zombie movie ever made is Aliens. Because the zombies are an actual threat. George Romero (who wrote "ghouls", not zombies) had ghouls as stand-ins for our hatred of humanity and our tendency to fuck each other over from the get-go. Since not enough people got it the first time, he set Dayn of the Dead in a goddamn mall. That dead horse was beaten in '78. Even that is a bad reading of a 1954 Matheson novel. If I had any input I would put Orfanato at the top of your list, followed by The Devil's Backbone. The stuff I worked on is terrible in every possible sense and you will grow stupider by watcing it. And I say that as the only person paid to work on Birdemic 2 (who was also smart enough to leave his name off it).