When The Empire Strikes Back was released 40 years ago, it was simply the sequel to Star Wars. It was not yet Star Wars: Episode V – The Empire Strikes Back, the middle chapter of a nine-film “saga” told in three trilogies. It was not yet subject to the obsessive tweaking that George Lucas started to do with the special editions two decades later, with their digital polishing, retconned bits of storytelling, and added characters and dialogue. And it was not yet freighted by spinoff projects, a splintered fan culture, and a mythology that’s complicated by the incompatible, sometimes contradictory visions of multiple film-makers and a corporate parent fussing over its investment.

Watching The Empire Strikes Back in 2020 isn’t exactly the same as watching it in 1980: the special edition, though not as aggressive as the other two in the first trilogy, has officially supplanted the original film and has a much glossier texture than other films at the time. Yet it nonetheless feels so simple and pure and liberating, not least because the future of the whole unwieldy franchise can be forgotten for 127 minutes and the past is only the 1977 Star Wars, which here serves as the first act that does all the heavy lifting for a second that only has to step on the gas.

The first Star Wars was made as if there would never be another – and based on reactions to Lucas’s rough cut, success was far from assured – but The Empire Strikes Back was made with the next film in mind, which presented a storytelling challenge that was not common at the time. It’s a narrative with no beginning and no end, starting with the assumption that the audience that will know the characters and the events that preceded it and then further assuming the audience will comfortable without a conclusion. Lucas himself had a good handle on serialization – Raiders of the Lost Ark, which he would produce a year later, was inspired by old adventure serials – but many critics at the time were flummoxed, like the New York Times’s Vincent Canby, who likened the film to “reading the middle of a comic book”.

Now that such serialization has become common, it’s easier to appreciate how Lucas and his collaborators – director Irvin Kershner, and screenwriters Leigh Brackett and Lawrence Kasdan – seized on the advantages of opening in medias res and closing on a cliffhanger. (And not just any cliffhanger, but an actual setback, with key players of the Rebel Alliance separated and Luke Skywalker having lost a duel with Darth Vader.) All the throat-clearing necessary is a scroll informing us that Imperial troops are chasing rebel forces across the galaxy, and that Luke (Mark Hamill) and the freedom fighters are hiding out in the inhospitable ice world of Hoth. From there, The Empire Strikes Back can immediately barrel into a series of thrilling images and set pieces: Luke and his tauntaun attacked by a wampa, a creature that looks like a Rankin-Bass abominable snowman; Han Solo (Harrison Ford) strikes out after dusk to track Luke down, facing temperatures so deadly that C3PO estimates a 725-1 chance of survival; and a probe finally locates the rebels on Hoth, leading to a siege by Imperial walkers, war machines that can’t be penetrated by laser fire, but are vulnerable to harpoons and tow wire.

The blockbuster was still in its infancy when The Empire Strikes Back was produced. Though Jaws is credited with the dawn of the blockbuster age, it wasn’t as if studios immediately started filling up the summer with big-budget entertainments every week. The original Star Wars followed through on the commercial promise of Jaws, but it was this sequel that set the standard for the decade where the model changed forever. To watch that breathless sequence of events on Hoth now is to see a combination of efficiency and spectacle that blockbusters have been chasing ever since – rarely with the same success, even in the seven films that would follow it in the Star Wars saga.

Conceiving the film as a relentless chase across the galaxy also gives Lucas and company the chance to immerse itself in world-building before it became a crippling obsession in the prequels. From the sub-arctic extremes of Hoth, which recall the Siberian wasteland of Akira Kurosawa’s Dersu Uzala, The Empire Strikes Back stages action in beautifully conceived new environments: The fetid swamplands of Dagobah, where the centuries-old Jedi master Yoda (voiced by Frank Oz) takes cover; the art deco sheen of Cloud City on the planet Bespin, which seems to reflect the slick, beautiful, opportunistic soul of Lando Calrissian (Billy Dee Williams); and the grim catacombs of a giant asteroid, where Han, Leia (Carrie Fisher), and Chewbacca (Peter Mayhew) hide out after the hyperdrive on the Millennium Falcon sputters out like an old Buick.

All these clean, distinct, meticulously realized settings and set pieces exist in support of the series’ most powerful revelation: that Darth Vader, the fearsome antagonist of the series, is actually Anakin Skywalker, Luke’s father, a Jedi who was seduced by the dark side of the Force. Now Luke, the sandy-haired naif of Star Wars, who we’d understood as an uncomplicated and gung-ho hero, has to contend with a much more uncertain destiny. Lucas would need the entire prequel trilogy to explain how Anakin’s sand-hating petulance would lead him to Emperor Palpatine’s side, but The Empire Strikes Back suggests that possibility for Luke with the same dramatic swiftness and power of the rest of the film. Luke’s failure to accept Yoda’s pleas for patience and discipline at Dagobah feeds directly into his confrontation with his father, who intends to reward his worst instincts. It didn’t take an entire prequel trilogy to realize that father and son have a few things in common.

After The Empire Strikes Back, the Star Wars saga would surrender to the ungainly and sentimental Return of the Jedi, and never quite find its way back to a film that’s as simultaneously streamlined and complex. The operatic qualities of The Last Jedi come closest, but by then, the series had taken on so much weight from its patched-together mythology and accumulation of old and new characters that it couldn’t move at the same speed. It’s an all-killer/no-filler Star Wars movie, a steady escalation of action that’s already in progress from the moment it starts. The series would never – and can never – be this good again.