Gone with the Wind
Gone with the Wind was one of the biggest movies in cinema history – both in terms of production scale and box office reward. People still like to point out that, when inflation is taken into account, it is the highest-grossing film ever.
The posters are also very clever in that a “bad thing” that happens in each movie is obviously lurking in the background. For The Empire Strikes Back, it's obviously the looming figure of Darth Vader and for Gone with the Wind, it's the great fire.
Yoda
Star Wars’ place in history was cemented before The Empire Strikes Back was released, but you could argue that the little green guy, Yoda, really elevated the franchise to new levels. This seemingly happy-go-lucky goblin turned out to be a Jedi Master who would train Luke Skywalker to become a great Jedi in his own right.
A key to the success of Yoda was the puppetry skills and voice talents of Frank Oz. The momentum of The Empire Strikes Back actually led to a campaign to get Oz nominated for an acting Oscar. However, it came to nothing.
The legacy of Boba Fett
“I know”
While the line is often described as being ad-libbed by Harrison Ford, he didn't simply make it up as he was going along. It was a suggestion that came out of rehearsals and not the scripted line of “I'll be back.”
That big twist we're still talking about four decades later
Darth Vader’s confession to Luke that he was his father in The Empire Strikes Back is considered by many movie fans to be the best plot twist of all time. Bigger than the one in Planet of the Apes, bigger than the one in The Sixth Sense, and bigger than the one in Psycho.
A New Hope clearly intended that Vader and Anakin Skywalker were different people – please recall Obi-Wan’s expository scene with Luke which explained how Vader was seduced by the dark side and killed Luke’s father.
So it was a great move to introduce the best bad guy ever as the father of the hero.
So why is this movie so popular?
It’s a dark tale that has no real ending, but it did feature one of the greatest movie twists at its highest point.
Consider the aforementioned The Sixth Sense. Would it have been any good if Bruce Willis was actually alive and the movie had a slightly different ending? No.
If the twist had not been in The Empire Strikes Back, one could argue the movie would have merely been classed as a good one, rather than a great one.