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?
In the scene where Luke 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?
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.
Contested Sequel: Given its status among fans as an Even Better Sequelthese days, some may be surprised to learn it was contested back when it was originally released. Unlike the first film, the second one ended on a cliffhanger that would only be resolved three years later with Return of the Jedi, making it easier to appreciate when the entire trilogy could be binged on home video than on initial release. The romance of Han and Leia, likewise upset many viewers who felt that the first film hinted Luke and Leia as the romantic leads, and the famous plot twist was seen by many as an out-of-left-field turn for a character who had been established in the first film as a one-dimensional villain. R2-D2 and C-3PO spent most of the movie apart from each other, meaning their much-liked dynamic wasn't present most of the time, and the latter had nothing to do except be whiny extra baggage. On the other hand reviewers did praise the new characters such as Yoda and Lando Calrissian, as well as the new locations such as Hoth, Dagobah, and Cloud City.
Continuity Lockout: While the opening crawl does explain the general events of what's going on and it's not too hard to follow the plot, this film does have a few plot points that would confuse newcomers who didn't watch A New Hope, such as the context of why Obi-Wan appears to Luke as a ghost and Luke's initial training with him, and why Han leaving the rebellion to pay off his debt is such a problem with Leia.
Crosses the Line Twice: 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 execition 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.
Designated Villain: Everyone (notably Han, Chewie, and Leia) treats Lando like a selfish coward for selling out his friends (who were soldiers), ignoring the fact that he had a city of millions of civilians to protect. If anything Lando's willingness to chose his duty to protect his people over his friends proves he's officially put his old ways behind him and grown to take his responsibility seriously. Might even be a contributing factor to why he got a promotion to general in the next movie.
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.
Franchise Original Sin: As this article explains, the very notion of a Star Wars sequel, albeit one which is regarded (nowadays) as a great film, might have cost the franchise its luster and originality. To quote the author, "The magic of A New Hope tricked us into believing that we were watching one chapter in an ongoing epic. A few years later, when it really was one chapter in an ongoing epic, the magic faded" i.e. the original Star Wars was sold as a Genre Throwback to the serials, while The Empire Strikes Back with its smaller cast, low-stakes, and cliffhanger ending setting up plots to be resolved in later movies, hewed even closer to the original B-serial in its storytelling and form. In the process, it set up a trend for all blockbuster films to come.
"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.
Yoda's warnings to Luke that he needs to be willing to sacrifice his friends for the sake of everything they fought for looks even darker than it already did after Revenge of the Sith revealed that Vader wasn't able to do that, and it ended in disaster for the whole galaxy.
Yoda telling Obi-Wan that after Luke, there is another, thanks to Luke dying in The Last Jedi and Carrie Fisher passing away in December 2016 after completing filming for that same movie.
Not only that, but as she's being pulled away by the Imperials, she screams once more, "It's a traaaaaaaap!!!!"
In Return of the Jedi Leia says "I know. Somehow I've always known." when Luke tells her that she's his sister. So, about that kiss on Hoth, Leia...
The scene where R2 and Yoda fight over Luke's lamp was made even funnier when the prequels revealed that ESB was not the first time Yoda and R2 had met. It's somewhat comical to think that R2 probably realizes that he's dealing with one of the most powerful beings ever to have lived... and decides to continue trolling him anyways, though it's possible that, knowing who Yoda is, he figures Yoda knows what he's doing by not revealing himself to Luke, and is just playing along by pretending to fight with him.
Han's "I know" to Leia's "I love you" was improvised by Harrison Ford, as he felt Han's scripted line "I love you too" was out of character. In Working Girl, Ford is the one who says "I love you," to which his love interest replies "I love you too."
Han's kissing Leia before being frozen in carbonite, while Darth Vader is present in the same room, is funnier after Leia is revealed to be Luke's long-lost sister and, therefore, Darth Vader's daughter. This means Han kissed Leia in front of her dad!
Although Darth Vader created the Darth Vader Clone, the most famous aspect of this film related to him, his relation to Luke, had been done 4 months earliernote albeit with a brother-sister relationship instead of a father-son one by one of his expies. Hell, the DVC there, Char Aznable, even tells Sayla Mass (who is in Luke's position there) to join him!
Luke being missing at the beginning of the movie, especially the "Nobody knows where he is!" exchange between Han and C-3PO, became this after Luke became Sir Not-Appearing-in-This-Trailer for The Force Awakens and "#WhereIsLuke" started trending on Twitter as a result. He is even missing in the movie itself and most of the plot revolves around finding him.
Since Revenge of the Sith shows only C-3PO got his memory erased, then this means R2-D2 knows Luke and Leia are siblings. It's not hard to imagine if he might have astromech equivalent of feeling Squicked out inside him upon seeing Luke and Leia kissed, but had to keep himself quiet, either to maintain the masquerade or possibly he's programmed by Bail Organa not to tell anyone about it.
The callsign of the pilot that retrieves Han and Luke from the Hoth wilderness is Rogue Two.
Similar to the high ground moment in Return of the Jedi, the scene where Han shuts down his power and hides in the Star Destroyer's garbage, only to be Out-Gambitted by Boba Fett, becomes more amusing following Attack of the Clones, where Obi-Wan hid from Boba and his father, Jango, by landing on an asteroid, powering down, and ejecting the spare parts canisters. Boba obviously learned from the experience.
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.
Luke, I am your father!note Vader: "Obi-Wan never told you what happened to your father." / Luke: "He told me enough! He told me YOU killed him!" / Vader: "No, I am your father."
"That's not true, that's impossible!"
"Search your feelings. You know it to be true!"
"I love you."
Never tell me the odds!
"Why you stuck up, halfwitted, scruffy-looking NERFHERDER!"
"Luke, don't! It's a trap!"note Yep, Leia said it three years before Admiral Ackbar did.
"You said they'd be left at the city under my supervision!"
"I am altering the deal. Pray I do not alter it any further."
"Obi-Wan has taught you well."
Lando had no choice.Explanation Lando was given a Sadistic Choice by Darth Vader: cooperate with the Empire or have his city destroyed and people killed, so understandably he had no choice but to comply to protect his city and people. Later, he muttered "I had no choice" once when he revealed he sold them out and once when he decided to double-cross the Empire and help Leia, Chewie, and C-3PO escape. In the latter's case, Leia mocked him while he's strangled by very angry Chewie, "Oh, of course we understand, don't we, Chewie? He had no choice."
In a meta sense, it is now common for parents to record showing their young kids the big scene and uploading their reactions to YouTube.
"So long, Princess."note Han Solo's goodbye to Leia before he attempts to leave to payoff Jabba the Hutt became a common tribute to Carrie Fisher after her death in 2016.
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.
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) was a real Mood Whiplash, which accounted for the mixed reception the film had in its year of release.
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 the film as "Best Star Wars film" or "darkest film" or even best sequel for any film, is harder to appreciate for newer 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 and the foreshadowing from the previous movie could have referred to a different kind of father. 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.
Mostly averted, however, with replacing the original Emperor hologram with Ian McDiarmid, as not only does this maintain tighter continuity, but McDiarmid simply is Emperor Palpatine to many, and his performance is seen as much better than the rather monotone voice-over Clive Revill provided in the original version. The fans who complain about this change are actually in the minority. However, some added dialogue for Palpatine and Vader 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.
They Wasted a Perfectly Good Plot: Boba Fett is the only bounty hunter seen after Vader puts a price on Han. It would've been interesting to see some competition between them for who can capture Solo.
Tough Act to Follow: Oh, so very much. Nearly forty years after its release, and with eight (and counting) 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: The film, while commercially successful, was not as popular as A New Hope when released, and Return of the Jedi was seen as a return to form after this. However, the films then started to be released on home video, and those watching it there started seeing this as better than the other two. Now it's considered the best film not only in the original trilogy, but out of all the Star Wars films in general.
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.