The force is with you, young Skywalker, but you are not a Jedi yet.

Rating: 10/10 (28 February 2017)

It's often said that The Empire Strikes Back is the greatest Star Wars film simply because it's dark. You've heard it before, people telling you it's the best because "the ending is so dark". While I do think this is the best film out of the series, I don't agree with that reason. I think the movie is dark as the result of what actually makes the movie so great. I will attempt to explain my point of view.
In A New Hope our heroes were part of a story that was bigger then them. It was about the Empire trying to wipe out the Rebel Alliance. In contrast the story of Empire Strikes Back is driven by the characters. The Rebels are still trying to free the universe from the Empire, it's just not the main story anymore. It's the backdrop of the story. The real story is Darth Vader's obsession with turning Luke Skywalker to the Dark Side. That is the driving force behind everything that happens in this film and suddenly the story is much more personal for our heroes.
This of course ends up giving a fantastic character arc for Luke, something that was missing from Episode IV. The heroic and hopeful Skywalker gets put through the wringer and by the end of the movie everything he believes in is now in question. It also leads up to one of the most memorable twists in movie history (which brings into question what order you should be watching these films).
Not to be left out though, and maybe something that goes overlooked by some, but Leia and Han have great character arcs as well. The incredibly self-reliant Princess is left emotionally vulnerable while Solo goes from self-serving to selfless. It's done so well you won't notice until it's too late. Of course this also leads up to one of the most memorable cliffhangers in movie history.
Character driven story. Great character arcs. One of the greatest twists and cliffhangers in movie history. Some truly iconic film moments. Those are the reasons why Empire Strikes Back is such a great film. The end result of those things make the film dark.