I think it’s the ****ty effects that made this so creepy lol …
Gone

I remember The Day After. I remember thinking it was well done.

Japan:
The Last War - 1961. Yes even Japan got in on a Nuclear War movie of their own. I mean, who knows the aftermath of an atomic war better than them? (not funny, okay.) Not a bad flick for it's time. Don't expect Godzilla or flying robots. This film, stands well on it's own. I think the full film is on YouTube.
The film begins with a narration over shots of a modern-day Tokyo, noting that 16 years have passed since the end of World War II, and Japan has achieved rapid recovery.
Five ICBMs are eventually launched from both sides in the climax of the escalating war, with targets being major cities around the world including Tokyo, London, Paris, New York and Moscow. The Tamura family stay behind in the midst of the city's panic and hold a final dinner. That night, Tokyo is enveloped in a flash of nuclear light and blown apart, with the ground being torn asunder by the explosion and resulting in a violent volcanic eruption that almost completely consumes the wreckage of the city. Tamura and his family are killed by the detonation over Tokyo as their house is blown away by the ensuing fireball. Shortly after Tokyo is destroyed, the remaining four missiles strike their targets, obliterating all of them. The next morning after Tokyo's decimation, Takano's ship changes course to arrive at the remains of the destroyed city, prepared to die by the intense radioactive fallout. ..
"That's a dumb question, Miss Glenn’s Organ."

You've seen Guy Standeven in something because the man was in everything.

The Divide, great opening Nuke explosion scene!
"That's a dumb question, Miss Glenn’s Organ."

You've seen Guy Standeven in something because the man was in everything.

You've seen Guy Standeven in something because the man was in everything.

Boy and his Dog
When the Wind Blows
Keep em coming!
"That's a dumb question, Miss Glenn’s Organ."

Ho Ho Ho

Italy:
Creation of the Damned (1974) - North America, in the near future. Two married couples live in a strange apartment that is actually an anti-atomic shelter. The world has been devastated by a nuclear war and the group waits for the radioactivity to disappear.
https://www.imdb.com/title/tt0072071/
I have this film on DVD. Can't find it online anywhere. This just one snippet from You Tube:
Italy knows how to make a nuclear war movie! After an Atomic Attack, there are still buildings and fully stocked grocery stores!
"That's a dumb question, Miss Glenn’s Organ."

Wow, nice one. thanks!
"That's a dumb question, Miss Glenn’s Organ."

Threads
is my personal favourite! Fantastic and frightening film.
There Will Come Soft Rains
, based on the short story by Ray Bradbury, is a great short depicting the aftermath of nuclear war:
Hark! Harold the angel sings.

Oh yes, The War Game. I wanted to add that one, but wasn't sure if anyone would remember it. And On The Beach.
"That's a dumb question, Miss Glenn’s Organ."

The War Game (1965) UK
Made by the BBC who then decided not to show it so it went to the cinemas.

It had a temp glitch but it's working again.
Ho Ho Ho

Seems fine to me.

Is youboob acting up for anyone else?
Ho Ho Ho

Well, these movies are old. You can, kinda, giggle a little at them now. But still scary.
"That's a dumb question, Miss Glenn’s Organ."

Of that list, I've only seen
The Day After
and
Threads
. They were good but I'd never rewatch them. I actually don't like nuclear war or post apocalyptic movies. Too depressing.

DefCon4 is truly dreadful.
Threads was amazing. The greatest antinuke film ever.
Would add: On the Beach (Australia/US)