If you want something a bit different, seek out Threads. It's on the Internet Archive (here, in fact)

Not a traditional horror film at all, it's set in the north of England in the early 80s (depending what n where you're from, the accents might prove a challenge!) and shows the ordinary people of a small city gradually coming to terms with escalating tensions between East and West, which result in all out nuclear war.

And then we get to see the actual on the ground nightmare that that would be. Not in a showy Hollywood way but in a grim, horrifyingly real feeling gritty British drama way. Bleak isn't the word.

It's something that's never quite left me since I saw it for the first and so far only time some years ago. Truly disturbing, and not fun at any point after things start getting serious. Brilliant though.