Aerial Canyon Chase: Han Solo and the Millennium Falcon do this during the famous asteroid chase scene. As Solo was noting, "They'd be crazy to follow us." Unfortunately, Darth Vader is quite a motivator for his troops and they dive in after him.
Artistic License - Physics: The gravity on the asteroid they land on should be incredibly low. When they are in the Falcon, it can be explained as Artificial Gravity, but later they go outside to investigate and the gravity is still normal.
Even if it were a large asteroid, for example, Ceres only has 1/36 the gravity of earth.
Author Existence Failure: George Lucas hated the process of scripting the first film, so he hired noted pulp SF novel author and Golden Age Hollywood screenwriter Leigh Brackett to write the script for Empire. She wrote one draft, but died of cancer soon afterwards. As a result, Lucas wrote the next few drafts himself, before asking Lawrence Kasdan to do revisions. Incidentally, the famous Luke, I Am Your Father reveal wasn't in Brackett's draft; Lucas only added it when he started rewriting the script himself.
Badass Normal: Boba Fett, while operating with very cool technology, is just a normal human yet can still stand up to Vader and order Imperials around.
Badass: Darth Vader is a badass throughout the trilogy, but it is most pronounced in this film.
Bad Boss: Vader personally Force-chokes two of his officers for their perceived incompetence (one of them did have lapses of judgement, but the other arguably did not), being the Trope Namer for You Have Failed Me. And he sends several Star Destroyers into the asteroid field to look for the Millennium Falcon, causing at least one to suffer catastrophic damage.
The Bad Guy Wins: Played with. The Empire crushes the rebels at Hoth, forcing the good guys to flee, but this doesn't defeat the Rebellion. Additionally, the good guys then get trapped in an asteroid field and then barely escape with their lives. Darth Vader (almost) defeats Luke in a lightsabre duel, cutting off his hand but Luke's virtue proves too strong to turn, and Han Solo is captured by Boba Fett and then frozen in carbonite to be taken to Jabba the Hutt. Are you wondering why this film is called The Empire Strikes Back, yet?
Bald of Evil: The scene with Vader in his medical chamber is the first time the audience sees a glimpse of what he looks like underneath his helmet.
Batman-Gambit: Vader wants Luke, but after the Hoth evacuation, he has no idea where to start looking for him. Instead, he pursues and captures Han and the others. While capturing them would be of value to the Empire regardless, Vader doesn't even have to bother sending out a villainous threat. He correctly anticipates Luke sensing their suffering through the Force and racing to the rescue.
Yoda (to Luke as he is about to leave Dagobah): Stopped, they must be. On this all depends. Only a fully trained Jedi Knight will conquer Vader and his Emperor. If you end your training now; if you take the quick and easy path as Vader did, you will become an agent of evil.
Bounty Hunter: Vader hires some when the Imperial fleet loses track of the Falcon, including Boba Fett.
Broken Pedestal: Anakin Skywalker. His son used to think he was a noble Jedi Knight that died years ago at the hands of Darth Vader. Now he knows not only did he not die at Vader's hands, he is Vader.
Captain Obvious: 3PO says the asteroid the crew is on "might not be entirely stable", right after the ground shakes. Han calls him "the professor" right after that.
Carnival of Killers: The bounty hunters, including a slimy reptilian (Bossk),a cyclopean droid (IG-88), an insectoid droid (4-LOM), a creepy scuba suit-wearing bug (Zuckuss), an armor-clad and mysterious badass (Boba Fett), and a man in bandages (Dengar). At least one Imperial officer is incensed that he's been forced to allow them aboard his ship.
"Bounty hunters! We don't need their scum!"
Cave Mouth: The crew of the Millennium Falcon confuse a space slug's mouth with an asteroid cave.
Cold-Blooded Torture: Vader has Luke's friends tortured in Cloud City, and they are mystified why they are not asked any questions. In reality, Vader is just doing it to lure Luke to him.
Cryptic Conversation: Yoda and Obi-Wan's conversation about Luke's father on Dagobah make a lot more sense when seen in view of the entire trilogy, as well as the There Is Another scene.
Curb-Stomp Battle: The Battle of Hoth. A lot of Rebel soldiers and equipment lost, at the cost of two AT-ATs, an Imperial-class Star Destroyer, and a few Snowtroopers.
Curb Stomp Cushion: The Rebels do manage to take out two AT-ATs, and a Star Destroyer is disabled, breaking the blockade around Hoth and allowing the Rebels to escape and regroup.
And as Spencer Ackerman famously argued, if Vader hadn't been so concerned with personally taking Luke, smarter Imperial tactics could have ended the Rebellion right then and there.
The fight between Luke and Vader. Inexperienced Force-user vs. a Dark Lord. As the fight continues it's clear Luke is hopelessly outmatched especially after Vader cuts his hand off. Worse, Vader is beating up Luke spiritually, taunting Luke to use his anger to defeat him and then, just Luke is clinging for dear life over an abyss, reveal that he is Luke's father. By the time Luke is rescued by his friends fleeing Cloud City, he's both a physical and mental wreck.
Damage Control: Han and Chewbacca are shown trying to get a malfunctioning hyperdrive online while being pounded by Imperial Star Destroyers.
Dangerously Genre Savvy: Even though Vader uses his leverage against Lando to keep Leia, Chewie, and the droids on Cloud City, he also has the sense to repair the hyperdrive of the Millennium Falcon but deactivate it, just in case they try to escape. As the hyperdrive is technically working perfectly, any hunt for problems will be a wild goose chase. Luckily for the rebels, R2 reactivates the hyperdrive just in time.
Disconnected By Death: During Vader's teleconference with the Star Destroyers' captains, one hologram image flickers and vanishes after the ship is struck by an asteroid.
"Imperial troops have entered the base. Imperial troops have entered [static]"
The Dog Bites Back: A subtle one. When Lando discovers that Vader was most likely not going to hold his end of the bargain after giving him Han Solo, he subtly contacts Lobot to orchestrate the Imperial boarding party's arrest by the security guards so he can get C-3PO, Leia, R2-D2, and Chewbacca out and hopefully save Han Solo.
Downer Ending: The Rebels are on the run, Han's been kidnapped, Luke's hand has been cut off, and his soul is profoundly shaken by Vader's claim to be his father, leaving the awful suspicion that his mentors Obi-Wan Kenobi and Yoda have lied to him.
Bittersweet Ending: But the Rebels have survived, Luke has not gone over to the Dark Side (which has deeply disappointed Vader), he and his friends escaped and the view of the galaxy signals that while this story is ending, the series continues — the fight will go on.
Exactly What It Says on the Tin: The Empire strikes back in a big freaking way in this film. By the end of the film, the heroes have really got their work cut out for them.
Exposition of Immortality: Yoda already looks like he's seen his fair share of years; walking stick, not much hair, crotchety old man. And clearly, he's been around for a while if he was the Jedi Master who trained Obi-Wan Kenobi, himself no spring chicken by Episode IV. Nevertheless, a sense of his true age is held back until he turns around and says:
"What know you of ready? For eight hundred years have I trained Jedi. My own council will I keep on who is to be trained."
Foiler Footage: Before the movie's premiere, the number of people who knew about The Reveal could be counted on one hand: George Lucas, Irvin Kershner, Gary Kurtz, James Earl Jones, Mark Hamill and whatever editors Lucas trusted to see the scene. Even David Prowse, who had to say something during filming, was given the fake line "Obi-Wan killed your father." Urban Legends now abound of Harrison Ford turning to Hamill in the middle of the premiere and giving a Big "WHAT?!".
Foreshadowing: The scene where Luke enters a cave on Dagobah and hallucinates about decapitating Darth Vader, and Darth Vader's face changing into his own. In hindsight, it's a clear warning of where Luke might have gone. Vader's line, "Only your hatred can destroy me," is a foreshadowing of the final duel in Return of the Jedi.
Four-Star Badass: General Veers, one of the few Imperial officers shown to actually be competent in the movies.
Genius Bruiser: This film both emphasized not only how big of a Badass Darth Vader really is, but how intelligent he is.
Grew a Spine: Luke, when he left Yoda's training to save Han and Leia.
Heroic BSOD: After Luke escapes from Vader and is rescued by Lando and the others in the Falcon, Luke has a major one. In the Falcon's cockpit as the heroes try to escape from Bespin, he's clearly filled with despair, whispering, "Ben, why didn't you tell me?" It doesn't help that Vader was using the Force to more or less "torture" Luke with the previous reveal of Vader being Luke's father.
Leia: You think that after what you did to Han we're gonna trust you?! (Chewie strangles Lando) Lando: I had no choice! C-3PO: What are you doing? Trust him! Trust him! Leia: Oh, we understand, don't we Chewie? He had no choice. Lando: I was just trying to help!
Late Arrival Spoiler: Darth Vader is Luke's father. The prequels have effectively made it a non-spoiler now.
A Lesson In Defeat: Yoda sends Luke into the cave to experience the dark side of the Force. When he thinks he kills Vader, the mask explodes and reveals Luke's own face, showing that he could give into the dark side himself.
An alternative interpretation of the scene, supported by the radio adaption of Empire, is that Yoda is showing Luke what is holding him back, namely himself and his own attitudes. Yoda tells him explicitly that he won't need weapons, and that the only thing in the cave is what he takes with him.
Limb-Sensation Fascination: Luke gets a new hand at the end. After being pricked with a needle to check pain sensation, he flexes his fingers a bit and clenches a fist while examining his bionic hand.
Little "No": Luke says this before it turns into a Big "NO!" after Vader reveals that he is Luke's father.
Love Theme: "Han Solo and the Princess", prominently heard during Han and Leia's scene aboard the Falcon.
Meaningful Echo: Lando's Ironic Echo (mentioned above) of Han's line also serves to show Leia, Chewie and the audience that there is more to Lando than the betrayal he was forced to make, that Han was right about him and Lando being so much alike, and that he is now in this together with the rest of the gang.
Moving the Goalposts: Lando tried to make a deal with Darth Vader, agreeing to help capture his old friend Han Solo and his companions in exchange for the Empire not killing everyone in his city. Vader kept altering the deal, because Lando realizes too late that he's completely powerless.
The Musketeer: It's not as obvious as other examples of this trope but Luke carries his blaster and lightsaber into battle together (mostly evident in the climax where goes from shooting Stormtroopers to dueling with Vader). It's the only movie in which he does this as well as the only time in the entire film franchise we see a Jedi or Sith doing it.
Must Make Amends: After the deal falls apart, Lando tries his best to save them.
Naval Blockade: When the Imperial fleet arrives over Hoth, they form a blockade to prevent Rebel ships from escaping, but they didn't seem to count on them having an ion cannon capable of disabling a Star Destroyer.
An Offer You Can't Refuse: Lando Calrissian had to turn Han and his friends in to the Empire, due to the alternative being to have Cloud City be attacked by the Empire and either occupied or worse, destroyed by them.
Lando: I had no choice. They arrived right before you did. I'm sorry.
Off-the-Shelf FX: Due to the scale necessary for the Star Destroyer's bridge model, ILM used an off-the-shelf Millennium Falcon model kit for the shot where the Falcon is hiding on the back of the bridge.
Both a potato and a shoe were used during the asteroid field scene. The shoe has a rumored story too - The rumor in question being that George Lucas asked the FX crew to redo the scene so many times that they got annoyed and one of them threw in their shoe. The potato can be seen in beginning of the scene in the top left corner.
The look on Piett's face when the Falcon finally gets the hyperdrive fixed just before the Star Destroyer can lock on the tractor beam. He knows the price of failure: Vader Force-chokes you. Luckily for Piett, Vader is more disappointed than angry.
Cpt. Needa when they lose the Millennium Falcon (hiding on the Destroyer's surface itself), and realizing he has to own up to Vader that he let them get away.
The look on Hobbie's face when Leia reveals the escape plan from Hoth.
"Two fighters against a Star Destroyer?!"
Out of the Frying Pan: A rather protracted example: Han Solo flies into the asteroid field to escape the Imperial fleet. He does escape, but realizes the interior of the asteroid field is just as dangerous, so he lands in a cave on a larger asteroid. The cave turns out to be a space worm's mouth. Fleeing from that, Han winds up right back where he started, with the Imperial fleet pursuing him again.
Plummet Perspective: It's a long way down from Cloud City. If you know anything about gas giants, it's even worse, as there's really no bottom; you'd just keep falling until the atmospheric pressure crushes you.
Ray Of Hope Ending: Han has been captured, Luke has lost his hand and had a pretty nasty revelation, the Rebels are on the run, but the heroes escape and are making it clear that they're not giving up, they are going to save Han and they are going to prevail. It might take a while but they will win.
Luke got bashed around by the wampa because Mark Hamill got in a car accident.
Rescue Hug: While the Millenium Falcon is inside the asteroid, there's a sudden tremor. Princess Leia falls backward and Han Solo catches her. He doesn't let go immediately, and continues to hold her even after she gets uncomfortable and asks him to let go. They then have a bit of banter that's intended to foreshadow their growing attraction to each other.
Retcon: Darth Vader was not planned to be Luke's father when Star Wars was made.
Rule of Three: C-3PO describing the ridiculous odds against whatever Han Solo's trying to do. The Millennium Falcon failing to jump into hyperdrive when needed. Vader choking his subordinates for failing him.
Running Gag: Again, the hyperdrive on the Falcon failing. By the third time, Leia and Chewie just kinda look at each other, neither one of them surprised at all. Eventually, Chewie goes into a rage, and Leia just does a Face Palm.
Scream Discretion Shot: The infamous torture scene. All we see are the the sparks and Han convulsing, but the worst of it is heard while Lando and Boba Fett are looking at each other, Lando being the most disgusted.
Secret Test of Character: After being told by Obi-Wan Kenobi to go to Dagobah to find Yoda, a great Jedi Master, Luke heads there after helping the Rebellion evacuate from Hoth. However, the only sentient life he finds is a really small creature who has a habit of searching through his things, and speaking in riddles. Luke gets flustered when the creature seems to continue wasting his time in search of Yoda, who then reveals himself to be Jedi he was searching for in the first place.
Self-Destruct Mechanism: The Imperial probe droid that discovers the Rebel base in the Hoth system has one, presumably to prevent anyone from capturing and identifying/analyzing it.
Sequel Escalation: The movie has more locales, more action, and features the first Luke/Vader lightsaber duel. While the Force in the first movie was vaguely defined telepathic and telekinetic powers, Empire shows the Force can also give you superhuman physical abilities and low-grade clairvoyance.note Although the clairvoyance part was hinted at in the previous movie.
Shipped in Shackles: Han Solo is frozen in carbonite for his trip to Jabba the Hutt. Vader plans to use the same procedure on Luke so he can be taken to the Emperor without escaping or fighting back.
The Starscream: Darth Vader, as revealed in the climactic confrontation. He appears to abandon this idea after Luke rejects him and the Dark Side.
Vader: Luke, you can destroy the Emperor. He has foreseen this. It is your destiny! Join me, and together, we can rule the galaxy as father and son!
Though he may still plan to do this in Return of the Jedi. In fact, the prequel trilogy would establish this as being the way of the Sith.
Stealth in Space: Han's successful attempts at hiding from Star Destroyers (but not from cunning bounty hunters).
Stern Chase: The cat-and-mouse between the Falcon and the Imperial fleet.
The Stool Pigeon: Lando Calrissian was forced by the Empire to sell out Han Solo and his friends to the Empire because they threatened total occupation/total annihilation of Cloud City if he didn't. In other words, he's closer to the Lacerated Larry type.
Throw It In: When they just couldn't get Han's response to Leia in their last scene right, Irvin finally just told Harrison to get in character and they would just run the scene without him being given a line to see how he would react, and he just blurted out "I know." The original line was "I love you too." Ford argued that Han Solo would never say such a thing directly, much less repeat someone. Lucas and Kershner agreed.
C-3PO (conversing with R2-D2): "Why didn't we just go into lightspeed? We can't? How would you know the hyperdrive has been deactivated?! The city's central computer told you? R2-D2, you know better than to trust a strange computer!"
Training from Hell: Fond of it, Yoda is. And steal your lunch, he will. Heck, Yoda even lampshades it, when Luke says he's not afraid.
Wham Episode: Okay, even though it's not a secret any more, Vader being Luke's father was a huge shock when the movie came out. And all the rest of the stuff at the end. Also "There Is Another", which resulted in a lot of debate at the time. Han was a favorite candidate.