Earth-Shattering Kaboom: Minor example. When Phil is briefing Tony early in the movie, there is a Freeze-Frame Bonus at the right of Tony with a clip of the SHIELD base after Loki's portal explodes. It looks like a nuclear crater.
Easily Thwarted Alien Invasion: The Chitauri turn out to be a Keystone Army, and other than their Leviathan transports are inferior to Loki's generic human soldiers. Lampshaded in The Stinger, they were expecting negligible resistance from a race of pushovers going by what Loki told them.
Eat Me: Tony's approach to a giant alien Leviathan with impenetrable armor. It's even lampshaded by Tony, who asks Jarvis immediately beforehand if he's ever heard of the story of Jonah from The Bible.
Epic Fail: Loki attempts to subdue Hulk in Stark Tower by yelling at him. It gets him slammed into the ground repeatedly mid-speech. Granted, Loki was having a Villainous Breakdown, but it still wasn't one of his better ideas.
Maria Hill shows up in the beginning of the movie, butts heads with Nick Fury over the evacuation of a S.H.I.E.L.D. facility, and gets into a car chase with an escaping Loki that ends up with her driving backwards at full speed trading gunfire with another vehicle, all before the title credits.
In his first five minutes, Loki slaughters half-a-dozen S.H.I.E.L.D. personnel, puts the mind control whammy on some main characters, and steals the MacGuffin.
Black Widow's first appearance in the film has her utilizing the rather unique interrogation techniques on some rogue Russians, and then kicking ass and taking names when Coulson contacts her about Hawkeye being compromised by Loki.
It's subtle, but Bruce Banner's humanity is the first thing established about him. When a little girl comes begging for his help healing her sick father, Banner's compassion overrides his better judgment; in fact, this is the bait Black Widow uses to draw him into their initial meeting. This moment is an extremely effective contrast with the jibes later in the movie about Banner being a "beast" or "monster".
Eureka Moment: When Stark is discussing Loki's actions, he mentions that Loki wants his name on his own personal monument, then realizes he built such a place, with its own unlimited power source.
Everybody's Dead, Dave: A deleted scene shows Steve Rogers looking at folders about his former allies Howard Stark, Jim Morita, and James Montgomery Falsworth are listed as dead. Peggy Carter is listed as retired, and Bucky is declared MIA.
Evil Brit: Played straight with Tom Hiddleston's Loki, subverted with the British member of the World Security Council, and averted with Jarvis. Also averted with Thor. Although Chris Hemsworth is Australian, Thor speaks with an RP accent (of varying quality).
Evil Is Hammy: While Loki is still subdued compared to Thor or Odin, he still gets his moments of this when he wants to make a speech or some grand gesture.
Tony: ...And Loki, he's a full-tilt diva! He wants flowers, he wants parades, he wants a monument built to the skies with his name plastered on— (realizes he's describing Stark Tower and in turn, himself) Tony: Sonofabitch.
Explosions in Space: Done correctly at the end of the film. The nuke Tony steers into the Chitauri mothership detonates as an expanding sphere, with no mushroom cloud or Planar Shockwave.
Hawkeye, while Brainwashed and Crazy, has a decidedly blunt approach to bypassing retinal scanners, and Loki is happy to oblige him. It's presumed that the remote eyeball thing that Loki jams into the German scientist's head is at least painful, if not resulting in the loss of the man's eye.
Hawkeye shows a desire to "shoot an arrow into Loki's eye".
Loki's dramatic failure to brainwash Tony thanks to the latter's miniature arc reactor.
Thor throwing his weight around with Loki, ordering him to "Listen well, brother..." He doesn't get too far in his speech before Iron Man rockets into him and tackles him off the cliff.
Fake Nationality: invoked Black Widow, being a master manipulator and spy, can pass herself off pretty convincingly as an American. Whether this is done deliberately by the film makers or it's a case of Scarlett Johansson Not Even Bothering with the Accent (the character is traditionally portrayed in most iterations with said accent and using Gratuitous Russian) isn't elaborated upon.
Natasha Romanoff: Regimes fall every day. I tend not to weep over that, I'm Russian — or I was.
Family-Unfriendly Death: It goes by very quickly, but when the Hulk is fighting several Chitauri on a rooftop, he palms one guy's head and crushes his skull like a grape.
Also when Cap fights the Chitauri after giving orders to the NYPD he grabs one of their arm cannons, cuts the arm off and then dumps it out of the gun.
Fanservice: Pretty much every character at some point either, if they're a lady, show off their behind in tight spandex, or if they're a dude, their chest in tight muscle shirts, or wears a suit that exposes their bare and toned arms.
Fantastic Racism: Loki views humans as an inferior race meant for slavery. He sums up this opinion pretty succinctly when he and Thor are talking on the mountain:
Thor: You think yourself above them? Loki:Well, yes.
Fatal Family Photo: Coulson's trading cards. Tony also makes mention of a cellist girlfriend whom Coulson had been seeing in his spare time.
Fate Worse than Death: The Chitauri have something special planned for Loki, should he fail to fork over the Tesseract. Since Loki fails to take over Earth, he better hope that his Asgardian brethren protect him indefinitely by locking him up. God only knows what his benefactor will do to him for the rest of eternity if he finds Loki.
The Other: You think you know pain? He will make you long for something as sweet as pain.
Fauxshadow: Come on, you know you thought the Mjolnir/Cap's Shield shockwave trick was going to come in handy during the climax... but it doesn't.
Female Gaze: The male heroes' chiseled physiques are often on display. Even their civilian clothing often includes tight muscle shirts. However, only a newly de-Hulked Bruce Banner is seen shirtless.
Selvig managed to install a fail-safe in Loki's portal that would allow it to be shut down, even while he was deep under Loki's control.
Some hints that this is happening to Hawkeye. He shoots Fury in his armored vest, which Fury notes in a deleted scene. Also, when Loki asks him what the Tesseract showed him, he responds "My next target," while looking at Loki. And more than that, when fighting Natasha (his closest friend) on the Helicarrier, both his arrows fail to hit her. The first one she had sidestepped at close-range before he even fired, but the other was from a distance... which he's best at.
The Hulk helps out his fellow Avengers during the climactic battle, in contrast to attacking them earlier in the film. Either Banner's feelings toward the rest of the Avengers have changed, causing the Hulk to behave differently toward them, or Banner is actively guiding the Hulk's actions from the inside. Banner himself always attempts control over the Hulk, as quite plainly demonstrated by his first involuntary Hulk-out: he gives Natasha an utterly anguished look as the transformation takes hold, and actively hurls himself away from her as the change takes place.
Fire-Forged Friends: An element of the story is that the members don't get along at first but eventually become friends and learn to work together.
The Leader — Captain America. Type II in practice and Type IV in theory. It takes him a while, but eventually he realizes his good heart and tactical knowledge are what is needed to bring the team together.
The Lancer — Iron Man. The total opposite of Captain America and the most resistant to being a team player. However, his loose cannon recklessness saves the day several times and conversely it is eventually he who benefits the most from having people watching his back.
The Smart Guy — Bruce Banner was reassured he was recruited for his scientific expertise and that his purpose was to track the Tesseract. Aside from the climax this is his purpose. Stark, also being a super-scientist, is a secondary example but fits Lancer better. The two of them bond over Techno Babble.
The Chick — Black Widow, by virtue of being the girl of the group, her ability to get to places where people don’t want her to be, and her use of emotions to manipulate villains. She's almost a heroic version of the Dark Chick.
Five Rounds Rapid: The NYPD is seen firing at the Chitauri with just their handguns. Possibly subverted, as Black Widow also uses handguns and is shown to be rather effective with them, although she trades up for a looted Chitauri weapon.
Fix Fic: Fix-fics where Coulson doesn't actually die and was actually just in a coma, because Fury tricked the Avengers into thinking he died to give them a "push" are so common that if you didn't watch the movie, you'd think it was canon — hell, fics where he actually is dead as per the events of the movie are a rarity, and even then he is often brought back to life with comic book style shenanigans. The fact that the audience never actually sees the paramedics call the time of death, that the events of the movie (specifically, the revelation that Fury dipped Coulson's Captain America trading cards in blood offscreen and showed them to Cap as to make his death hit them all the harder) actually hint that the former explanation could very well be canon, and that the actor has signed up for several more movies with Marvel, make this trend far more plausible than most of the examples on this page.
Five-Temperament Ensemble: The five male members of The Avengers and even their most distictive colors fit a Combo Ensemble: Tony Stark/Iron Man (choleric gold + sanguine red), Thor (choleric red and yellow + melancholic black), Bruce Banner (melancholic/phlegmatic green when he turns Hulk — which is ironically the only time he appears not to fit his respective temperament), Steve Rogers/Captain America (phlegmatic blue + sanguine red), and Clint Barton/Hawkeye (leukine, neutral grey/black).
Loki's favorite tactic. However, Tony correctly spotting that Loki's ego (similar in size to his own) could make him sacrifice pragmatism for showmanship means this trope comes back to bite Loki hard.
Black Widow also makes use of his love for the Breaking Speech and "The Reason You Suck" Speech. The Chitauri use his thirst for vengeance and "worthiness" to make him his errand boy to fetch the Tesseract; in exchange, Loki gets Earth, which they don't give a damn about.
It's taken to ridiculous extremes with Tony to the point where it's not just that he stands in stark contrast with every other main character, but even with himself, (Tony at the beginning vs. Tony at the end).
Bruce Banner vs. Tony Stark: Both are genius-level scientists, and harbor mutual respect for each other. While both have a dark side, they are completely different personality-wise. Bruce is, by necessity, mild-mannered and cautious to control his id, while Tony's flamboyance and irreverence are the tip of his self-destructive decadence.
Tony Stark vs. Steve Rogers: Apart from being tied by family history, both are motivated by a sense of American patriotism and a desire to end wars and bring peace to the world. But Tony and Steve are completely different in terms of temperament and modus operandi, and Steve has uneasy memories of having worked with Tony's father. According to Robert Downey, Jr., Tony has heard so much about Steve from his dad that he's like a big brother he can never live up to. Also noted is that Steve and Tony are the two main benefactors of Howard's legacy: Steve couldn't have received the Super Soldier Formula without Howard (he wouldn't have even met Dr. Erskine if he hadn't watched Howard's performance), while Tony inherited everything from his father.
In an odd contrast, going back to their origin movies, how they received their powers and what they had before them are on the opposite ends of the spectrum: Steve had no physical resources, but had the moral and personality traits necessary for super-heroism, and was handed the Super Soldier Formula on a platter. Tony, who was given a lot of outside resources but nothing internally, didn't just have to build his armor, but he also had to create the whole superhero mindset from his previous status as a "genius billionaire playboy philanthropist". On top of that, Steve received his powers because he wanted to go from his life to the front lines, while Tony built his so he could escape for his life from the front lines! Heck, even the scientific workshops where their powers began; Steve's was nicely furnished, clean, run by a government agency, while Tony's was in a cave with a box of scraps. Then there's the chase post-lab shootings, Steve's running to catch an enemy and with Tony, the enemy is chasing him!
It reaches the point where it just somehow suffers from Steve not bringing up a few stories about Howard, or at the very least a photo of the Captain and Howard together (but if Pepper Potts almost didn't appear in the movie, then there's no way that was making it in.)
Thor vs. Steve Rogers: Both are old-fashioned in ideals and aesthetics, initially felt ill at ease on modern Earth, and are driven by a sense of duty before their homeland. Still, both find it difficult to comprehend each other — they are two very different kinds of old-fashioned, after all. They also share a lack of understanding of modern idioms. Thor and Steve's origins are also from opposite directions. Thor was born into power and privilege, a spoilt, proud, but well-meaning child, abusing his strength as a bully. Steve was a sickly, skinny little orphan from Brooklyn, weak and poor, but possessing an unshakable sense of justice, standing up against those he felt needed standing up to despite his weakness. Thor was stripped of his gifts and learned humility. Steve gained strength as a reward for his virtuous nature.
Steve Rogers vs. Bruce Banner: It's only touched on briefly, but Steve Rogers is the Super Soldier experiment gone right, while Bruce Banner is the experiment gone wrong (or "wrong").
Natasha Romanoff vs. Clint Barton: Secret agents with Dark and Troubled Pasts, a sense of chilly professionalism, and a deep, long-standing friendship originating when Clint made a choice that perhaps Natasha wouldn't have.
In addition, Loki has traits that resonate or clash with the leads: Asgardian origins (Thor), intelligence, mercurial temperament, and love for theatrics (Iron Man), manipulation of emotions (Bruce Banner), disregard for freedom and human life (Captain America), a lack of empathy (Black Widow), and a disregard for free will (Hawkeye).
All four of the main powered heroes have different ways by which they acquired and use their powers. Iron Man had no power, but built them on his own in a time of crisis. Thor was born with power, then stripped of them and learned humility to use them responsibly. Bruce Banner was given power he never wanted, and it is a struggle for him to control it. And Captain America was born with weakness, but granted power by a benefactor. Iron Man has some resentment towards this in particular because he's the only one whose abilities, aside from his intellect and charm, could be realistically negated. (You can't untrain Widow or Hawkeye, nor is there anyone to strip Thor of his powers, cure Banner of the Hulk, or negate the Super Soldier Serum in Rogers.)
Tony: You're a lab experiment, Rogers. Everything special about you came out of a bottle.
When Thor arrives on the scene, the first thing he does is rain lightning down on the soldiers threatening the Badass Normals. Cap then charges Thor (one of only two members of the team that could fly high enough) with using his lightning as artillery to bottleneck the Tesseract portal.
But even moreso, this is Iron Man's specialty. His armor is extremely fast yet highly maneuverable, which is a huge advantage against the Chitauri. Furthermore, because of his speed and firepower, Cap places him in charge of containing the enemy to a few blocks. To see just how well Tony can pull this off, check out his feats in The Oner. He provides cover for Black Widow, Cap and Hawkeye in the span of a few seconds.
Food End: At least in the U.S. release. There's Shawarma!
When Loki is being led to his prison onboard S.H.I.E.L.D.'s airship, he briefly smirks at Bruce Banner. Guess what his real reason for being captured is.
Not long before The Reveal, Coulson makes an offhand comment to Thor that he "changed everything".
Very subtly done in the scene where Natasha and Banner meet for the first time, when she has a child lure Banner to a isolated house in order to ask him to return to SHIELD. Pay close attention to the background when Banner is speaking. There are many green objects and green streaks of paint, all in sharp focus. When Natasha is shown, there are also green objects and green paint, but further in the background and out-of-focus. As the scene progresses, the green objects behind Banner get more obvious. This progression coincides with Natasha slowly realizing that the Hulk is very close and she starts treading very lightly.
Cap telling Tony that he's not the kind to sacrifice himself for a greater cause.
A very subtle one in the beginning: Barton shoots Fury on the chest, even though he would have normally been able to hit him on the head. It shows that Loki's Mind Control is not 100% perfect. Later it turns out that the brainwashed Selvig was able to install a backdoor to turn off the Tesseract and the portal.
Loki's new staff that was given to him by the Chitauri's leader. With its distinctive blue gem and mind control powers hints that it is the mind gem from the Infinity Gauntlet and that the leader is Thanos.
Very early in the battle with the Chitauri, one of the air speeders chasing Iron Man smashes into a building because it couldn't turn fast enough. Barton later points out their poor maneuverability to Tony, who immediately puts the knowledge to deliberate use.
One for Iron Man 3 with Tony testing out a new device that'll allow him to call his suit to him in case of long distance emergency. He expands upon it in the third film.
Watch carefully when Nick Fury brings out Coulson's blood-stained trading cards and says he got them from Coulson's jacket. Agent Hill gives Fury a "What the hell?" expression. Later she calls Fury out on this saying that the trading cards were actually in his locker.
When Tony arrives on the bridge and starts dumping exposition, he pauses to shout "That man is playing Galaga!" The primary objective of Galaga is to shoot aliens descending from the top of the screen, which is exactly how the final battle plays out.
Dark Energy Space Telescope (DESTINY) (ok, that one is stretching it)
Supernova Acceleration Probe Lensing (SNAP-L)
Potential Energy Group/Alternate Sources/United States (Project PEGASUS) (The research facility where the movie begins.)
Generation Xerox: Captain America's initial dislike and butting heads with Tony Stark mirrors the relationship he had with his father, Howard. Although not as unrealistic as it's usually done, since Tony displays a lot of his father's quirks and attitude.
Tony eventually figures out that Loki's set up the Tesseract at the top of Stark Tower because of Loki's ego.
Stark and Banner collaborate theirs to figure out the truth about what S.H.I.E.L.D. wants with the Tesseract. Being a organization of spies, they must have some kind of hidden purpose.
Steve: You think he's holding something back from us? Tony: He's a spy. He's the spy. His secrets have secrets.
Captain America and Fury both realize Loki gave up far too easily.
Thor: Loki is a prisoner. Nick Fury: Then why do I feel like he's the only person on this boat who wants to be here?
Towards the end of the fight between Natasha and a brainwashed Clint, he looks up and says her name with a bit of tenderness to get her to ease up. She punches him in the head again.
And during the battle in New York, Hawkeye switches around the arrowhead of the arrow he shoots at Loki, just in case he manages to catch it. He's actually witnessed Loki's physical speed and senses firsthand at the start of the movie, so he knows that it is entirely possible Loki could catch the arrow.
Central to Black Widow's interrogation techniques is the fact that she knows Bad Guys just love to Monologue.
During the assault on the SHIELD Helicarrier, Coulson knows who's really behind it, and goes straight to the weapons locker to get the BFG.
The World Security council scrambles two nuke-equipped F-35's. Just in case Fury shoots one down, as he did.
Steve does a subtle one to Tony when the latter, not having Cap's combat experience or training, is having a Heroic BSOD over Coulson's death.
Thor gets a second one when he first confronts Hulk on the Helicarrier. He tries to get through to Banner. "Banner, try and think. We are not your enemy." Unfortunately, Hulk wasn't in a mood to listen.
Loki's scepter trick fails on Tony, who notes that "performance issues" affect about "one in five."
Tony's line to Banner suggesting he uses a "big bag of weed" to stay calm is said very quickly, probably for this exact reason.
When Tony asks Pepper what they would do if she "bunked over" in his tower, she whispers something in his ear. His expression says it all.
When Natasha is being "interrogated" by the rogue Russian officer, she mentions that she knew what he "had planned" for the evening before she was "captured" and that she prefers the situation she's in.
When Natasha tries to convince Bruce to join the team, Bruce asks, "What if I refuse?", to which Natasha replies with a small but earnest smile, "I'll persuade you."
Glasses Pull: Done by Coulson in the first scene of the film. Especially notable because those were sunglasses and was during the night.
Go Karting with Bowser: As mentioned below, Tony pours himself a drink as he talks to Loki and even offers him one.
Loki has developed a full-blown god complex — which is rather appropriate, given that, in the Marvel Cinematic Universe, Asgardians were mistaken for and worshiped as gods.
Black Widow: They're basically gods. Captain America: There's only one God, ma'am, and I'm pretty sure He doesn't dress like that.
Loki later tries to give his A God Am I speech to the Hulk. Let's just say he won't be doing that again anytime soon.
Thor also starts slipping into this when everyone in the lab argument scene was succumbing to the discord field that Loki's staff was giving off.
Godwin's Law: Invoked, appropriately enough, by Captain America, who compares Loki to man he dealt with "the last time I was in Germany." Possibly subverted, however, in that he may technically have been referring to Red Skull rather than Hitler.
Godzilla Threshold: Fury states that the events of Thor proving humanity wasn't alone in the universe prompted S.H.I.E.L.D. to initiate Phase Two in the event that a hostile alien threat attacked Earth and crossed the threshold. Later, the WSC decides to go ahead and nuke Manhattan, in the event that the Avengers can't force the Chitauri back. Also discussed by Loki and Nick Fury.
Loki: How desperate are you? That you call on such lost creatures to defend you? Fury: How desperate am I? You threaten my world with war, you steal a force you can't hope to control, you talk about peace, and you kill 'cause it's fun. You have made me very desperate. You might not be glad that you did.
Also, in a more literal sense, Captain America telling Bruce Banner that now might be a good time to get angry.
Tony Stark is of course a conceited and arrogant jackass who has problems with authority, but still a man who wants to make up for his past failures.
Thor still has shades of being a Boisterous Bruiser that smashes first and asks questions later, but he follows his heart and demonstrates Undying Loyalty to his family, allies, and the Earth itself.
The Hulk is a rampaging id monster which smashes friend and foe alike during his temper tantrums, but just because he doesn't like you doesn't mean he won't protect you. Simultaneously, just because he fights alongside you for the same cause doesn't mean he's above sucker punching you later.
Hawkeye and Black Widow are assassins and former criminals who won't hesitate to do what needs to be done. That doesn't stop the two of them from being loyal to each other and to their comrades.
And Nick Fury, who will employ every dirty trick he can think of to get the job done. Of course, the job is preserving worldwide freedom.
S.H.I.E.L.D. agents are mostly armed with Glock pistols and M4A1 carbines. Bad guys use a mix and match collection of weapons that wouldn't look out of place in your average MW2 match or, in the case of the aliens, high-tech blasters.
The Reveal of Phase 2 being the reverse engineering and development of weapons based on HYDRA technology serves to sow quite a bit of discord amongst the heroes, partly due to them being left in the dark about this plan. Captain America and Thor in particular are very upset by this, for different reasons.
Green Aesop: This is central to the plot. The Tesseract is a clean power-source, Stark Tower runs on self-sustaining energy, and so on. Although, one of the key fights of the film ends up leveling half a forest. It also causes severe complications at the climax — self-sustaining energy is hard to just switch off.
Guile Hero: Black Widow's favorite interrogation technique is to make the bad guys feel powerful with her acting skills and then listen to what they let slip in their victorious rants.
Guns Akimbo: The Black Widow uses two glock pistols at the same time fighting the Chitauri.
Guys Smash, Girls Shoot: A rare gender inversion in the team of Hawkeye and Black Widow: while both are entirely capable in the other field (she's a crack shot and he can certainly deal damage hand-to-hand), Natasha is the superior martial artist while Clint is the finer marksman.
The trope is still somewhat played straight in that while Natasha is certainly technically more skilled in hand-to-hand combat, Clint is still able to get the upper hand thanks to his superior brute strength, forcing Natasha to resort to more creative tactics in order to defeat him.
Loki's other favorite tactic; he was loving the chance to tear apart Black Widow from inside his cell.
This is also Black Widow's prefered method of interogation: get captured, act vulnerable and nail her "captor" with information they felt comfortable enough to share with their "victim".
Hate Plague: Not that the Avengers weren't getting on each other's nerves before, but it's implied that Loki's scepter somehow has the ability to supernaturally raise tensions between the team while he was on the Helicarrier. When Banner starts getting angry, he picks up the scepter without realizing it.
Headbutting Heroes: Thor and Tony's first encounter, when they fight over custody of Loki. Literally.
Heel-Face Turn: Subverted. In the fight between Thor and Loki, Loki starts to do this, but it turns out he was just playing Thor's emotions to get the upper hand in the fight.
Hero Insurance: After everything's said and done, one of the many news reports tries to blame the Avengers for the damage to the city. Fury conveniently fails to ask where the Avengers were going after their mission is complete, precisely to avoid such questions.
Hero of Another Story: Every member has had his own movie or at least a minor role (or cameo) in a previous film.
Hero Stole My Bike: The Avengers snag a S.H.I.E.L.D. quinjet to take to the final battle. An agent mentions they are unauthorized, but Captain America quickly shuts him up.
Heroic BSOD: Romanov is reduced to hugging her knees and shivering after a near-death experience against The Hulk. She snaps out of it when a call to take down Flying Monkey Barton is put out, though.
Heroic Neutral: Banner doesn't want to get involved in the fighting, mostly to keep Hulk at bay, but he changes after some character development.
Hesitant Sacrifice: Subverted. When Tony Stark sacrifices himself to save New York, he does so completely calmly and professionally, without a fuss, hesitation, or even any kind of acknowledgement or last words other than trying (unsuccessfully) to call his girlfriend to say goodbye. However, the expression of sheer, naked terror on his face as he flies himself into space through the portal, where he knows he will die, effectively serves this trope's purpose anyway. Tony survives just barely.
Black Widow uses a fallen alien weapon to use against them at one point, and is actually very proficient at it.
Loki's scepter serves as a tool for shutting down the portal to the other dimension.
Thor tries to fry Iron Man with a bolt of lightning. Though it causes some damage, it also charges the armor to quadruple capacity, which Tony uses immediately to blast Thor with a supercharged repulsor discharge.
In the movie Thor, Loki took control of the Destroyer and sent it to Earth to get rid of Thor. It also did a number on Agent Coulson's men. It was trashed and its remains were picked up by S.H.I.E.L.D. Fast forward to the present, and Loki is blasted through a bulkhead by an Earth-made BFG built from Destroyer technology, wielded by Agent Coulson. It doesn't kill or seriously harm Loki, but it probably hurt his pride at least a little.
Loki decides to hijack Stark Tower, and its arc reactor to power the portal. However, this gives Tony an opportunity to switch out the Mark VI suit, which had been severely damaged in battle, and get into the Mark VII suit. If the battle had been held anywhere else, Tony would not have had that opportunity, and would have been significantly less effective in battle.
It was SHIELD screwing around with the Tesseract that sets the whole plot in motion. But, in a bit of brilliance from Joss Whedon, it is also the portal being generated by the Tesseract itself that allows Iron Man to deposit a nuke right into Chitauri HQ, effectively stopping their invasion cold (and possibly wiping out their army altogether).
Fury attempts it against Loki during the opening sequence.
Later, Tony Stark's borderline Cloudcuckoolander monologue when he first arrives on the Helicarrier successfully distracts the group while he slips his hacking device onto a nearby computer.
Also, Tony's Badass Boast to Loki in Stark Tower was undoubtedly at least in part to stall for time while Jarvis prepped his Mark VII Suit.
Honor Before Reason: Captain America, while retaining his core sense of honor, averts this. Despite his initial insistence to Tony and Bruce that they should trust in their orders, Cap does take their skepticism seriously, and does some off-book investigating of his own. He ends up beating Tony to the punch in calling out Fury.
Hood Hopping: Cap hops along a few car roofs while avoiding explosions.
Human Popsicle: Unlike Captain America: The First Avenger, we do get to see Steve's frozen fate, which is briefly seen in a series of flashbacks that he has while working out.
Tony Stark: Yeah, you may have missed out a few things, doing time as a Cap-sicle.
Humiliation Conga: Over the course of the movie every single Avenger and Agent Coulson manage to land at least one good hit on Loki, with the amount of them increasing by the finale.
Captain America takes Loki in one on one combat. Though he manages to throw in a few quips and put up a decent fight, he's on the losing end before Iron Man shows up.
Nick Fury turns Loki's previous retort about how "an ant has no quarrel with a boot" on its head by locking him in an enormous cage and declaring himself the "boot".
Black Widow has a battle of the minds with Loki and uncovers his agenda while seemingly unfazed by Loki's Hannibal Lecture, but it ultimately does nothing to hinder Loki's Evil Plan, and it's later shown that Loki did get under her skin.
Coulson is fatally stabbed by Loki, but bravely tells him that Loki is doomed to fail. As the latter tries to retort, Coulson shoots him through the wall.
Iron Man likewise has a lecture battle with Loki, then is immune to his attacks. Both succeed, as Loki's plan follows through and Tony is only stalling, but Loki's Villainous Breakdown begins.
Thor is outsmarted by Loki earlier but when the two fight in the climax, he maintains the upper hand, forcing Loki to flee.
Hawkeye fires an arrow at Loki's glider, which the latter catches in midair before it explodes and sends him flying.
Captain America, as seen in his first onscreen appearance. He's seventy years out of his own time, everything he's ever known is gone, and nothing in the world makes sense to him anymore. Also, super-serum or not, the war took its toll on him. A deleted scene shows how out of time he is as he tries to wander around modern New York City. Whedon cut it because a) it made Cap's character too complicated (by throwing him out of time and giving him PTSD), and b) because the line of punching bags in the gym is more than enough to show exactly what he's going through anyway.
Also Bruce Banner. Though he tries to hide it through sarcasm. The "secret" to how he controls his transformation pretty much spells out much this trope applies.
Hawkeye, especially after being freed from his brainwashing. If he's lucky, he's going to be having nightmares for a while.
I Am Not Left-Handed: Bruce Banner's secret to keeping his Hulk Mode on standby is to stay just angry enough... all the time.
Once again, Thor initially holds back when fighting Loki, not wanting to hurt his little brother. And once again, Loki pushes Thor to far and is promptly stomped. Director Joss Whedon even described this point as Thor "finally having enough of Loki's shit."
"I Know You're in There Somewhere" Fight: Thor attempts this with Hulk the first time. Amusingly, the fact that Hulk sucker-punches Thor later on shows that the only thing "in there somewhere" was "the other guy".
I Need a Freaking Drink: Loki decides to take Tony up on his offer of a drink after he's defeated and cornered by the entire team.
I Surrender, Suckers: Loki gets captured and taken to the Helicarrier. He then uses this as a distraction while his men attack the Helicarrier and set up the Tesseract device right on top of Stark Tower.
Hawkeye's special power is his improbable accuracy with a bow. He manages to land a USB arrow into a computer, curve an explosive arrow around a ship to hit from the other side, and hits speeding enemy planes without even looking at them. Hawkeye later nails a Chitauri on one of their hovercraft while looking in the complete opposite direction. In one scene, Hawkeye is targeting some Chitauri chasing after Iron Man. If you notice, his bow is angled in a slightly different direction from where he's looking as he pans to track his targets. This is because he's leading the target.
Nick Fury lands a hit on the engine of a jet taking off, with an unguided RPG launcher, using iron sights, with one eye.
In Name Only: The alien invaders are called the Chitauri. In the comics, the Chitauri are the Ultimate Marvel version of 616 Marvel's Skrulls, shape-shifting aliens whose modus operandi is impersonation and infiltration (see the Skrull-centric storyline Secret Invasion). The movie Chitauri take a blunt Attack! Attack! Attack! approach. They do resemble heavily-armored Skrulls, however. The movie rights to Skrulls are technically tied to the Fantastic Four, and therefore owned by Fox. The choice to use the Ultimate equivalent is a conscious use of this trope.
In the Blood: Thor's "He's adopted" line always gets a laugh, but this is what he's really implying about Loki.
Tony: I don't know what it is, but I wanna try it.
Insistent Terminology: Bruce Banner does not turn into the Hulk. He turns into "the other guy". All the other characters continue to refer to his alter ego as the Hulk, however, and Bruce himself slips up once before correcting himself. This is likely Speak of the Devil — Banner doesn't want to give the Hulk any extra power.
Instant-Win Condition: Apparently, Chitauri all die if you blow up their command ship. The leading theory is that the Chitauri are somehow linked to their home-ship, similar to the Buggers in Ender’s Game. And since the Leviathan ship seemed to be biologically related to the Chitauri themselves, this is entirely plausible. Joss Whedon notes in the commentary that he didn't particularly want to do this, but the movie was already two hours long and it was easier.
Invisibility Cloak: A partial one. The underbelly of the S.H.I.E.L.D. Helicarrier displays the sky above the ship, making it invisible to ground-based observation.
Iron Buttmonkey: While Loki acts the part of an intimidating villain commendably, he gets many a moment of glory and gloating snatched from him by Coulson's last shot, Hawkeye's surprise bomb arrow, and Hulk beating him like a rag doll.
In Tony's introduction scene Tony is trying to convince Pepper to take some credit for the Stark Tower idea.
Tony: Give yourself 12%. (a bit later, when Agent Coulson interrupts them) Tony: I thought we were having a moment Pepper: I was having 12% of a moment.
"Well, let me know if 'real power' wants a magazine or something." In response to Loki's boasts.
When Loki first appears, Fury tries to defuse the situation by saying "We have no quarrel with your people." Loki responds "An ant has no quarrel with a boot." When Loki is captive on the Helicarrier, Fury says that one button is all it will take to jettison the cell, Loki included, and remarks (pointing at Loki) "Ant..." (points at button) "...Boot."
A more serious one: while ferrying Captain Rogers to the Helicarrier, Agent Coulson says that "Maybe people need 'old-fashioned'" in response to Captain America's traditional suit, but clearly referring to the ideals Captain America represents. Later, at the team's darkest moment, Fury suggests that believing in heroes might be "an old-fashioned notion."
Tony sarcastically remarking that Coulson's first name is "Agent", then later, "His name is Phil." Bonus points for it being said both times in the same room.
"Put on the suit." Takes on a new meaning when Banner swiftly and painlessly transforms into The Hulk.
Loki says of Hawkeye, just before he brainwashes him with the scepter, that he has heart. Coulson, just before owning Loki with the Destructor-based gun, says to Loki that he lacks heart.
In Loki's original A God Am I / "The Reason You Suck" Speech in Stuttgart, he says it's in humanity's nature to be subjugated. Later a dying Phil Coulson tells Loki he will be defeated, since it's in his nature.
It's Personal: Tony theorizes that this was Loki's purpose in attacking the Helicarrier while getting everyone to fight amongst themselves. He later congratulates Loki for making it this, as he's successfully managed to piss off every one of the Avengers.
It's the Only Way to Be Sure: The World Security Council decides to stop the Chitauri threat by nuking Manhattan (while the Avengers are still fighting there). Fury dismisses this as "a stupid-ass idea" and outright tries to prevent it. With a rocket launcher.
Black Widow's reaction when Cap asks what Tony is without his armor and he answers "Genius, billionaire, playboy, philanthropist".
And not long after,Tony to Steve "You're a laboratory experiment, Rogers. Everything special about you came out of a bottle". Harsh but true, compared to Tony and Banner's intelligence-derived powers and Black Widow and Hawkeye being trained, Cap's power was handed to him for being a Nice Guy. Also could be interpreted as Tony failing to see that it's not Cap's powers that make him special, it's his noble resolve.
When the Avengers learn that Fury weapons based on the Tesseract and everyone calls him out on it, he retorts that he had no other choice given how technologically inferior Earth is when compared to the other races on the universe like the Asgardians. Given that more than a few of them are aggressive, Fury's wariness is hardly unjustified.
Bruce: [chuckles, looksobviouslyamused and satisfied] I'm sorry, that was mean, I just wanted to see what you'd do.
Later in the Helicarrier, Bruce as The Hulk popping up out of nowhere and roaring at Natasha (again).
Jurisdiction Friction: S.H.I.E.L.D. and the World Security Council want Loki to be judged for his crimes on Earth, while Thor insists that he must "face Asgardian justice".
Just Plane Wrong: If you look at the scene where the S.H.I.E.L.D. F-35-lookalike jet is firing its guns, you'll see that the muzzle flashes are coming out of the jet intakes — an enormously bad idea as 1) you don't want to reduce the amount of air you can intake by having guns in there, and 2) you'll send the spent shells right into the jet engine.
Just Train Wrong: At the beginning of the scene introducing Black Widow we see an establishing shot of a Norfolk Southern freight train passing by the ratty looking warehouse where the heroine is conducting an interrogation. The only problem is that the scene is set in Russia where American locomotives cannot operate (the train tracks have different widths.)
Keystone Army: The Chitauri, apparently. Once Iron Man nukes the mothership, all units on Earth cease functioning. Whedon has said that he wasn't happy about using it, but needed a way to skip the "cleanup" phase of the battle.
Whenever Cap does anything awesome, notes of his theme plays.
Invoked by Stark when he flies in during the Captain vs. Loki fight. The stereo of the S.H.I.E.L.D. helicopter overhead is commandeered by Stark, and seconds before he shows up, "Shoot to Thrill" starts playing. It probably wouldn't count if Stark hadn't intentionally played the same song in his first scene in Iron Man 2.
Lensman Arms Race: Thor states that S.H.I.E.L.D.'s experiments with the Tesseract have started one: it's the equivalent of an otherwise unremarkable postage stamp in Eastern Europe or Africa suddenly getting a nuclear reactor and with their efforts to reverse-engineer HYDRA's weaponry, nuclear weapons. Once Earth re-ignited the Tesseract, it was no longer an Insignificant Little Blue Planet in the CIA Galactic Factbook — it's now a potential rival. And when the Avengers wiped out an entire force of Chitauri and thus earned Thanos' attention, it was equivalent to said postage stamp wiping out a Spetsnaz unit and thus earning Stalin's attention!
Let's Get Dangerous: Invoked by Nick Fury at the end, that Earth is no longer an insignificant little fish in the galactic pond.
Director: Was that the whole point of this... a statement? Nick Fury: A statement... a promise!
Thor's introduction, after Cap and Stark have "captured" the surrendering Loki, is to burst into their transport and remove his brother by force. This could prove an obstacle to saving their world, so both heroes jump out of the plane to give chase. The showdown involves a lot of snarking and pummeling, and answers the question of what happens when a near-unstoppable hammer swing meets an unbreakable shield.
Also, the Hulk briefly chases Black Widow and tangles with Thor when he first "meets" the team. Loki planned to use The Hulk to destroy the Helicarrier and all of his enemies along with it.
Lightning Bruiser: The Hulk is phenomenally strong even compared to the mighty Thor, but the movie also does an excellent job of portraying just how dangerously fast he can be for his size, particularly when he's tearing things up with remarkable agility in the final battle.
Also, the scene of him chasing Black Widow has her running for her life down a small corridor and Hulk catching up to her while smashing through barriers.
Living Legend: All the Avengers but mostly Captain America. Tony Stark uses the phrase itself.
The Marvel and Paramount logos are seen inside the Tesseract.
Also seen at the end of the movie. Stark Tower's "STARK" logo gets all the consonants removed during the final fight. What's left? A very stylish 'A', similar to the one in the classic "Avengers" logo.
Luckily My Shield Will Protect Me: After Captain America breaks up the fight between Tony Stark and Thor and tries to convince Thor to "put the hammer down", Thor acts on those words by smashing Captain America with it. Captain America blocks it with his shield, which indeed protects him from a blow from the hammer of a Norse god — by reflecting the force of the blow in all directions in a shockwave that levels everything in the immediate area.