A common fan theory is that Admiral Ozzel was a double agent or Rebel sympathizer, and so his seeming incompetence (not wanting to search the Hoth system, alerting the Rebels' to the imperial fleet's presence by coming out of light speed close to the solar system) was actually his attempt at undermining the Empire's efforts to find them. A few POV scenes of Ozzel in Legends render this unlikely in that timeline, as he is portrayed as demonstrably incompetent, disdainful of the Rebels, and primarily concerned with his own advancement.
Did Vader order his fleet to the Hoth System because he sensed Luke's presence? Or was he just desperate enough to find Luke that he jumped to the conclusion that the Rebels were hiding on Hoth the moment he saw the base's shield generator?
Considering the prequels revealed that Yoda and R2-D2 knew each other before their meeting here, is R2 fighting with the old Jedi Master over Luke's lamp him purposely trolling one of the galaxy's most powerful beings for kicks? Is he playing along with Yoda's decision not to reveal himself to Luke by pretending to fight him? Or does he blame Yoda for Anakin's turn to the Dark Side and the whole argument between the two is basically R2 Calling the Old Man Out?
In the scene where Luke silently jumps from the platform on Bespin after his confrontation with Vader, did he actually know that he'd be pulled into an air vent before the fall killed him? Did he intentionally save himself by using the Force to control his fall, or was he trying to kill himself before he succumbed to the temptation to accept Vader's offer, or out of despair over Vader's revelation? The 1997 Special Edition seems to lean toward the last bit, as it had Luke scream while falling via added audio of the Emperor screaming in Return of the Jedi, though later releases reverted to his silent fall because even Lucas realized it was a stupid addition.
"He's just a boy." Is this Vader expressing doubt over Luke being a threat to the Emperor, or is this Anakin Skywalker pleading for his son's life?
Award Snub: Many feel that Frank Oz's portrayal of Yoda was very underlooked, between his voice acting and puppeteering work. George Lucas attempted to campaign for him to get a Best Supporting Actor nomination at the Academy Awards, but the voters ultimately felt that it didn't qualify as a "real" performance.
Yoda's theme playing as he raises the X-Wing out of the swamp.
The suspenseful music that plays as Luke sneaks through Cloud City is very effective at setting the mood.
The love theme for Han and Leia.
Big-Lipped Alligator Moment: During the Battle of Hoth, there is a Blink And You'll Miss It shot of what looks like a little two-legged baby Imperial Walker. It does not appear in any of the wide shots of the AT-ATs advancing or at any other point in the battle. Though multiple, AT-STs have a much more prominent role in Return of the Jedi and they are well known through Pop-Cultural Osmosis, its presence in this film is an example of this trope. It's since been revealed one of the effects crew threw it in as basically a joke, only for Lucas to take quite a liking to the idea and give them a bigger role in the next film.
While this is par for the course with the changes made in the 1997 Special Edition and onwards, the new shots of the Wampa are some of the more hotly debated changes in the newer version, with some fans preferring the Nothing Is Scarier aspect of the theatrical version mostly keeping the Wampa off-screen, and others feeling that the new shots of the Wampa make the scene flow much better. For what it's worth, both George Lucas and Irvin Kershner disliked how the theatrical version turned out, as it had to be heavily cut down due to Special Effect Failure with the original Wampa costume.
Aside from the Wampa, and later Boba Fett's dialogue being redubbed by Temuera Morrison in the 2004 DVD edition, this is the only film where the changes made in the Special Edition are widely considered to enhance the film rather than detracting from it. The reshot Emperor sequence with Ian McDiarmid is often cited as an improvement over the original, the additional shots of Cloud City and the CGI windows replacing the white hallways are seen as adding more life and colour to the environment, and the Special Effect Failure of Luke turning transparent in the ending sequence is completely fixed up. However, it goes without saying that the original version will always have its defenders, and even people who prefer the Special Edition will still say that the original should still be available as a viewing option.
Very, very downplayed, such that we're only mentioning it here to clear a pervasive myth up. While it got an overall excellent reception from critics (who didn't consign it to the Sci Fi Ghetto) and fans alike, early on there was a bit of this due to some people being thrown for a loop by the cliffhanger climax and ending that would only be resolved three years later with Return of the Jedi, with the looming conflicts unresolved (unlike the first film's triumphant ending), Han's fate uncertain and Vader being revealed as Luke's father. This is due to the series being influenced by the conventions of Film Serials, which had then fallen out of fashion. While there were some who preferred the first film for being self-contained, this didn't stop Empire from topping the worldwide box office in 1980 and having three successful re-releases in theaters in the intervening years, as the twists left the audience eager for more, and it became even easier to appreciate when the entire trilogy could be binged on home video. In the very year it came out, so without the benefit of the passage of time, it even won Best Film at the People's Choice Awards.
Though with the release of the Prequels and Sequels and those films being dubbed as subpar follow-ups themselves by parts of the fandom, the canard that "people hated Empire at the time too" has somehow taken root due to defenders of the later films, bordering on Common Knowledge for newer fans the more it's repeated. Not only is this whataboutism, the "proof" is just taking those critics who didn't like the first film to begin with as representative of the critics and fandom at large. As much as the later films may be divisive, the originals were the ones that pretty much everyone liked, which enabled the later films to be made.
Any of the You Have Failed Me moments in this film qualify as this. On one hand, you'll feel disgusted or horrified with the executions. On another hand, you can't help but chuckle while thinking "Oh shit, I saw that coming." Admiral Ozzel's Force Choke execution is notable in that he gets to hear the news of someone else (Piett) getting promoted to his rank just as he's about to perish.
"Apology accepted, Captain Needa." Spoken by Vader after executing the poor sap.
Director Displacement: George Lucas was the executive producer, and neither directed nor wrote the final script for the film. He was however heavily involved in the conceptual stage, writing the original story with its central twist, the Han/Leia romance, Yoda, and the general overall tone of the film, which was intended to be a Genre Shift into horror.
Boba Fett. He had no more than four lines in the entire series and to this day is highly regarded as one of the most popular characters in the entire series, due to his mysterious nature, and his fearlessness even in the face of Vader (and, of course, his awesome armor).
Admiral Piett. Originally a one-off character, he was brought back for Jedi thanks to fan requests.
Kenneth Colley: "My character was not originally in Jedi. But George Lucas said, 'Ken, I've got a whole bunch of letters from people wanting to know more about Admiral Piett, and I want to put him in the movie. I have no idea what you're going to do but will you do it?"
The pilots of Echo Squadron have become quite popular in the EU, especially Wes Jansen and Derek 'Hobbie' Klivian. Not to mention Wedge Antilles, who was already an Ensemble Dark Horse from the first film.
The other bounty hunters qualify, too. At least Fett was in more than one scene; Dengar, Bossk, IG-88, 4-LOM, and Zuckuss just stand around looking cool on the bridge of the Executor and nothing else. This was all it took to get them all extensive backstories in the Expanded Universe.
Captain Needa, appearing in all of two scenes (and alive only in the first), won a lot of admiration for going to Vader in-person and taking full blame for losing the Falcon. It was clear that he knew he was going to his death, but he went anyway to protect his crew.
Between the release of this film and Jedi, there was a lot of arguing from fans over whether Vader had lied about being Luke's father (one of the proponents of this was none other than James Earl Jones). Lucas included the scene of Yoda confirming it in the next film specifically to kill any doubt.
On a similar note, Yoda's cryptic "there is another" comment ignited a firestorm of speculation.
Even Better Sequel: Critical and fan reception was overwhelmingly positive with many critics (at least those who liked the first film instead of dismissing the series as junk) calling it an improvement on the first film, if not just as good, due to factors like the character development of the leads, the new characters such as Yoda and Lando Calrissian and the new locations such as Hoth, Dagobah, and Cloud City.
"Funny Aneurysm" Moment: Before the asteroid chase, Han is trying to repair the Millennium Falcon when his toolbox falls on top of him, hurting him in the process. In June 2014, Harrison Ford got injured during filming for Episode VII when a hydraulic door from the Falcon set fell on top of him.
When he arrives on Dagobah in search of the wise Jedi master Yoda, Luke encounters a small green muppet who speaks in a funny manner. The film is clearly written with the intention of this muppet's identity reveal being a big surprise to first-time viewers... except that, since the film's release, everybody knows who Yoda is, including any new viewers who watch the films in numerical order, rather than release date order.
Moral Event Horizon: Vader subverts it again here, though this is merely the first subversion anyone saw, with his callous treatment of Lando on Cloud City. The next film has him confirm to Moff Jerjerrod with a straight face that that was just poking the poodle compared to what the Emperor is capable of, and even before his Papa Wolf moment in that film it's shown at the end of this film that he cares about his son, even if he's been tasked with turning him to the dark side.
Nausea Fuel: When Han cuts open Luke's dead tauntaun and all of its rubbery white guts spill out of it.
Its Atari 2600 game, which was not only pretty complex for a 2600 game, but also is considered one of the best licensed games on the system. Then fast forward to the mid-1990s and the Super Star Wars trilogy games.
The arcade game, made using the same graphics and the same engine as the previous Star Wars game.
One-Scene Wonder: Prints from the 2004 DVD onwards digitally add Ian McDiarmid in for The Emperor's cameo. This is the only Special Edition change most everyone agrees is an improvement over the original, as not only does it maintain tighter continuity, but McDiarmid simply is Emperor Palpatine to fans, and his performance is seen as much better than the rather monotone voice-over Clive Revill provided in the original version.
Sacred Cow: This film ties with A New Hope for the Star Wars film with the highest following. Even people who don't like the prequel and sequel trilogies will not pick on this film. Also, do not criticize the famous It Was His Sled scene if you know what's good for you.
C-3PO reached the level of scrappiness in this movie due to him gaining characterization by being a shrill worrywart that never shuts up and constantly rattles off unfavorable statistics about their current situation. He also can't keep himself from complaining to Chewie and R2-D2 when they repair his dismantled body. However, he is remembered much more fondly ever since the prequels introduced a certain Gungan.
Admiral Ozzel is an In-Universe example of this, with the novelizations establishing that the man was notorious for being shortsighted and not thinking through his strategies like his fatal maneuver at Hoth.
The famous scene really doesn't have the same level of suspense on later generations as it did at the time of its release, largely due to Memetic Mutation. Not having to wait three years to find out if it's true also helps. More than that, very few among the audience had reason to expect a plot twist of this nature to begin with. A New Hope was a Genre Throwback to B serials which largely didn't have such twists played for dramatic tragic effect, and while there was hype for The Empire Strikes Back it didn't lead to the great speculation audiences now have about any large blockbuster project. Audiences went in expecting more of the same old-fashioned B-Movie fun, and this kind of twist, which was not teased, nor promised, nor speculated upon, more or less made every other big-franchise twist either guessed at, speculated at, or obvious in its build-up and Foreshadowing.
Likewise, Darth Vader in the first movie and for most of The Empire Strikes Back was established as a consistent heel, torturing Leia, killing Obi-Wan, and in this film, putting Han Solo in carbonite, without any hint that there was more to him. For the film to pull off the twist so deftly that he goes from pure evil to ambiguous and empathetic in the final moments (such as when he stares sadly when Luke jumps into the vacuum on the bridge) kept people intrigued and eager to find out the truth and how it all ends until the third film finally came out. Nowadays it's no great surprise for series to drop huge twists and developments regarding characters for the sake of added complexity.
The cliffhanger ending was shocking at the time since this sort of thing simply wasn't done, though audiences were generally hyped up for the resolution even if they had to wait years. If you're binge-watching the films, it doesn't have quite the same impact, and it's not uncommon for middle parts of trilogies to have cliffhangers because of this film's influence.
The fact that this was a middle part of the story in the first place instead of a self-contained sequel was a major surprise back then. In comparison, the first film was self-contained with the promise of more adventures to come but not with dangling plot lines. And with the opening crawl first proclaiming this was "Episode V: The Empire Strikes Back" in the Star Wars series (the first film, then simply "Star Wars", got "Episode IV: A New Hope" in in its crawl after this was released), fans first realized the possibility of Episodes I-III at some point. This all seems a bit quaint compared to today where studios make their franchise intentions clear with new movies.
Also, a few aspects of Lando Calrissian and how he related to the real world can easily pass by many viewers born after the movie came out, or especially ones born in the 21st Century:
Firstly, his flirting with Leia. Today it comes across as just a bit sleazy, cements Lando as a would-be charmer but perhaps not as good a "scoundrel" as Han, and might even provoke a few accusations of the person of color being made to seem "aggressive", but when the movie was released, miscegenation laws were a mere thirteen years dead nationwide. The mere fact that Billy Dee Williams got to do this with Carrie Fisher, and that in-universe nothing was weird about it aside from making Han a bit annoyed for reasons that have nothing to do with race, was for many a sign of greatly changing times and still a big deal.
On that tack, the mere fact that Lando was played by Williams, a black man, and was in a position of authority over a city and that nothing was weird or out of place about this in a major mainstream film was a very big deal (and many folks of color of a certain age would cite it as an inspiration as late as thirty-five-plus years later). He does lose his authority, but this has more to do with sheer force and the overall tyranny of the Empire than it does any kind of racial reading.
The status of this film as the "darkest Star Wars film" or even a dark film in general is harder to appreciate for modern audiences. The Empire Strikes Back doesn't actually have any major Character Deaths and the only intense violence is Luke getting crippled at the end, the impact of which is immediately undone with a bionic hand that works far better than any real-world prosthetic, which fans of newer fantasy works like Game of Thrones, which treats a similar crippling incident as a traumatic Career-Ending Injury with actual story consequences, find unimpressive. Those who have seen the prequels first note that Revenge of the Sith with Order 66 and Anakin's massacre of the younglings was a much more violent and darker moment than anything in Empire, while fans of the Disney era point out the more visceral violence and action in both the sequels and Rogue One's hallway massacre scene is considered Vader's most horrifying scene in any Star Wars film.
Ship Sinking: Despite the kiss Leia gives Luke, the Luke-Leia ship that was established in A New Hope and later explored in the first sequel novel Splinter of the Mind's Eye as well as the Marvel comic book series, is sunk when it's established that Han and Leia are now a couple. (Three years later, Return of the Jedi would blow the Luke-Leia ship out of the water completely by establishing the two of them to be siblings.)
Shocking Swerve: At the time, Darth Vader telling Luke that he was his father. It came right out of nowhere, as the previous movie clearly said Luke's father was a hero whom Vader betrayed and murdered. It worked, nonetheless.
Largely on the planet Hoth due to technical limitations:
The Tauntaun shots have not aged well. The life-size puppets are fairly convincing, but the shots of them running are recognizably stop-motion.
The Wampa was mostly removed because of it in the original version. The Special Edition inserts newly filmed scenes of it.
During the AT-AT battle, the Snowspeeders (and related shots, as per Word of God) were not printed at their full opacity. This is evident in a view from the cockpit. Like the Wampa example, this was eventually fixed.
While it's easy to miss at first due to how fast it goes by, close examination of the part where Vader cuts off Luke's hand reveals that the blade completely misses his arm!
Luke goes a bit transparent when he falls down the Cloud City shaft.
When the Mynocks start swarming after Leia and Han, you can clearly see they're large sheets of plastic tied around poles because the head is completely absent from them, unlike the previous shots of them. Even Irvin Kirshner admitted that the reason they cut away from the Mynocks so quickly was because of how awful the props looked.
During the scene where Lando argues with Vader while Han is being tortured nearby, when Vader steps into the elevator and it closes, it doesn't properly shut and between the slightly open slits you can clearly see Vader's actor standing idly behind the doors while waiting for the take to end.
Squick: After Return of the Jedi, Leia kissing Luke on the mouth became this. Even though she states in Jedi that "somehow" she had "always known" that she was Luke's sister, she may or may not have done it to make Han jealous (in which case, that may or may not be an implied Retcon).
Suspiciously Similar Song: The Imperial March sounds a great deal like Prokofiev's "Montagues and Capulets". Not coincidentally, the two songs are juxtaposed on Epica's album The Classical Conspiracy.
In the George Lucas Altered Version, Boba Fett's voice is probably the biggest point of contention; while Temuera Morrison gives a decent performance, many people grew attached to Jason Wingreen's original voice acting as the character.
The 1997 Special Edition has Luke scream (for some bizarre reason dubbed in with a clip of Palpatine screaming from the following film) as he falls through the central shaft of Cloud City, which made it seem less like he was nobly choosing possible death over joining Vader, and more like he'd suddenly realized he'd have been better off joining Vader after all. Lucas himself evidently came to regret this choice, as the 2004 DVD release onwards has Luke falling silently again.
Some added dialogue for Palpatine and Vader's scene did add a new meaning to the scene, which threatens to lessen the dramatic impact of Vader revealing himself as Luke's father, though it's generally seen as subtle enough that plenty of viewers see the added dialogue as effective foreshadowing for the big reveal.
Another minor gripe but in the Special Edition and 2004 DVD release, the ad-libbed line "You're lucky you don't taste very good" which Luke says to R2 on Dagobah was changed to the original line "You're lucky to get out of there." Not a big issue but the former line just sounds better.
The special edition also sees fit to insert several new shots of Vader returning to the Excecutor during the climax, as well as changing his "Bring my shuttle" line to "Alert my Star Destroyer to prepare for my arrival". While there are those who appreciate the movie showing this since he originally seemed to get back to his ship unreasonably quickly, others think it breaks up the flow of the Cloud City escape, over-explains a plot-point that was fairly self-explanatory, and think the old line and and its much angrier-sounding delivery is more appropriate considering that he had just come so close to capturing Luke.
Tough Act to Follow: Oh, so very much. Over forty years after its release, and with nine films added to the theatrical franchise in the interim, it is still widely considered the best Star Wars film, with every subsequent film being varying degrees of Contested Sequel.
Vindicated by History: Downplayed. The film, while commercially successful, was still relegated to the Sci Fi Ghetto by those critics who dismissed it as mere kiddie or adolescent fluff like the first film. Fans and other critics were decidedly not on their side, and now it's considered not only the best film not only in the original trilogy, but out of all the Star Wars films, and one of the best Speculative Fiction works in general even as it and the franchise has influenced tons of other works.
The stop motion AT-AT walkers? The entire Asteroid field chase? The amazing matte and compositing work of Cloud City? This film fired on all cylinders for the special effects!
Also worthy of mention is Frank Oz's amazing puppetry of Yoda. Despite being a tiny foam latex hand puppet, at no point do you not think that he's a living, breathing character that is acting right alongside Mark Hamill on the set.