Coulson implies that one can be arranged if he doesn't get to talk to Natasha, right now.
Made of Explodium: Surprisingly averted. This is actually a superhero action film where people keep shooting at cars, planes, helicopters, etc. without most of them exploding.
There are even a few occurences where the trope is downright inverted: stuff that should logically explode, and it looks weird and unrealistic when they don't. For example when Nick Fury shoots a rocket at a plane trying to take off with a rocket launcher and it comes out of it with only a destroyed wing and (supposedly) no harm to the pilot.
Made of Indestructium: Being made of Vibranium, Cap's shield is used to block or reflect nearly every attack in the movie made against him (including Mjölnir, as Drop the Hammer shows), and only the paint is damaged.
And again when Loki shanks him in the gut in the the battle atop Stark Tower. He seemingly grabs his abdomen in pain, but promptly removes the blade, and proceeds to body-slam Loki. He then tosses the bloodied blade away with a look that says "Now, I'm pissed" and less "That hurt."
Make an Example of Them: Loki preparing to zap a mouthy old man standing amid his flock, before Captain America intervens.
Male Gaze: The movie does this a great deal with Black Widow and Maria Hill seems to be walking away from the camera in a lot of shots. Pepper Potts wears Daisy Dukes and bare feet during her cameo.
Tony's eyes are openly brimming with tears during the "we are not soldiers" scene after Coulson's death, although they never fall.
After Loki traps Thor in the cage and tells him that he's going to kill him, Thor is too heartbroken to respond, simply letting his tears fall as he averts his eyes from Loki.
Blink and you'll miss it, but a tear runs down Loki's cheek right after he stabs Thor in their fight on Stark Tower.
Market-Based Title: In the U.K., the film is known as Avengers Assemble, no doubt to avoid confusion with the classic British TV series of the same name. Strangely, the merchandising such as children’s toys all still bears the original title, next to posters with the revised title. For some reason, both titles were used to advertise it, saying that The Avengers would be released on the 26th, and Avengers Assemble being released on the 27th.
Massive Multiplayer Crossover: A rare live-action example. This movie is possible since all of these franchise characters are owned by Marvel, and also because the previous films of the team's big four (Iron Man, Hulk, Thor and Captain America, in this order) all lead up to this.
Maybe Magic, Maybe Mundane / Sufficiently Advanced Aliens: Downplayed, but present. Even with our current understanding of science fiction, some things the Asgardians do are just easier to explain with magic. People refer to Loki as "casting spells", often in the same scene as discussing Asgardian technology.
Meaningful Background Event: When Loki is talking to the Other, at one point, a giant snake flies past in the background. In the attack on New York, they end up using those things as weapons.
Meaningful Echo: Fury says that when Coulson died, he lost his one good eye. In Iron Man 2, as he's leaving Coulson to watch over Stark, he reminds Tony, "Remember, I've got my eye on you."
When Fury explains the Avengers Initiative, he finishes by saying, "It was an old fashioned idea," echoing Coulson's remark that "Maybe we could use a little old-fashioned."
Mid-Season Upgrade: Iron Man upgrades to the Mark VII armor during the film. It can fly by itself when deployed by Jarvis, track and line itself up with Stark using a pair of bracelets he wears, and assemble itself around him. Now Stark can don the armor no matter where he is. Also, the Mark VII's laser lenses do not eject after use, implying that they are now limited only by the suit's power source.
Militaries Are Useless: The National Guard is explicitly stated as being unable to stop the Chitauri invasion in New York City, even though the Chitauri soldiers and aircraft can be readily destroyed with modern weapons.
Millionaire Playboy: Tony Stark describes himself as a "billionaire playboy" as well as "genius philanthropist."
Mind-Control Eyes: When Loki controls people with the scepter. First, their eyes turn pitch black, then their irises and pupils turn the same shade of blue as the scepter's gem.
Mind Rape: Hawkeye's description of what it felt like to be brainwashed by Loki definitely gets into this territory.
Misfit Mobilization Moment: Coulson's death finally motivates the heroes to get together and, yes, avenge him. Thor sees the Son of Coul get skewered as he watched helplessly. Tony gets roused to action because Tony knew him the longest of all. Cap gets motivation from the bloodstained Captain America trading cards that Coulson so eagerly wanted him to sign. Romanoff and Barton have plenty motivation because they were all longstanding comrades in the agency. Only Bruce Banner isn't motivated by this event, because he wasn't there for it; he came back for other reasons.
Mistaken for Aliens: Played for Laughs with Bruce Banner. As the Hulk, he lands on a warehouse, half-destroys it and becomes human again. Then, he speaks to an old man, the security guard, who believes that Bruce is some sort of alien. The security guard is played by Harry Dean Stanton, who was in Alien.
Mood Whiplash: Joss Whedon indulges his penchant for intentionally derailing dramatic moments with a witty one-liners. They're better heard than read.
N.Y.'s new landmark, Stark Tower, gets trashed, as well as some famous real-world buildings in Manhattan.
Stark Tower itself is built on top of the Metlife building. Part of the background set up by the designers for the movie was that Stark literally built his tower over it, meaning the bottom of it would still be the real-life landmark.
Hawkeye wears a black outfit instead of his classic purple one from the comics. Also lampshaded by Captain America.
Captain America: Aren't the stars and stripes a little... old-fashioned? Agent Coulson: With everything that's happening, people might just need a little old-fashioned.
Inverted by the superhuman members of the main cast— Hulk, Iron Man, Thor, and Captain America wear pretty flamboyant, colourful attires (or are colourful in the case of Hulk). All protagonists clad head to toe in black (Black Widow, Hawkeye, Nick Fury, Agent Coulson) are Badass Normal at best.
Tony lampshades the trope by mocking Thor's "Shakespearean" attire, and Steve Rogers' "spangly outfit" (noting that Rogers wears the "Captain America" uniform constantly, as if it's casual attire).
Mr. Fanservice: Ladies, take your pick. The blond, clean-cut, blue-eyed, all-American Nice Guy? The tall, dark, and snarky genius billionaire playboy philanthropist? The pretty boy god with an accent? The Draco in Leather PantsBig Bad? The stoic, "cool loner" archer? The adorkable bespectacled scientist? Almost all of whom are incredibly buff and march around in skin-tight clothing, shiny badass armor, and/or sleeveless wardrobe with arms the size of tree trunks?
Georgi Luchkow, the Russian who Black Widow beats up early in the movie, shares his name with a minor Black Widow villain from the early '90s.
Romy Rosemont appears as Shawna Lynde, a Thor supporting character during the 1980s.
James Eckhouse appears as Senator Boynton, a minor character during the Armor Wars storyline. He is seen near the end, asking on a cable news show about where the Avengers are and who they should be accountable to.
The Tesseract facility at the beginning of the film is revealed to be Project Pegasus, a S.H.I.E.L.D. research sites from the comics.
"You have reached the Life Model Decoy of Tony Stark." Life Model Decoy is the term used for an entire sub-set of robotic "clones" featured in the comics.
The Captain America trading cards display artwork by Jack Kirby, save for the one that has a picture of Cap in his stage show outfit.
Loki has his mouth sealed shut at the end of the film, echoing his mouth being sewn shut by dwarves in Norse Mythology.
During Thor and Loki's conversation on the cliff side, two ravens fly past, evoking Odin's two ravens in Norse Mythology.
When The Other threatens Loki with "more than pain" should he fail, one of the Chitauri's giant snakes can be seen moving through the background. In Norse Mythology, Loki is punished for his role in Ragnarök by having a snake drip venom in his eyes for all eternity.
This one is half-Mythology Gag, half-Continuity Nod; Banner mentions that at one point, he tried to kill himself with a pistol "and the other guy spat out the bullet." This was going to be the opening scene in The Incredible Hulk film (and actually appeared in the Alternate Universe miniseries "Banner!") but was cut because Louis Leterrier, who directed this Hulk film, thought it would be too dark (and yet that scene showed up in the video game tie-in, as well as the novelization). Years earlier, this also happened in the comics.
While talking to Loki, Tony refers to the Avengers as "Earth's mightiest heroes", a moniker that has followed the team since day one.
Where the last couple Hulk movies referenced the character's iconic purple pants; Avengers reference is subtler by having Banner wear a purple shirt for most of the film.
Within the movie continuity, Hulk chasing Black Widow through a narrow corridor can bring to mind a similar scene from Iron Man where Iron Monger chases Pepper.
"To challenge them is to court death." The primary aspect of Thanos' motivations in the comic books is that he saw the personification of death when he was young... and fell in love with her. Now you know why he's smiling.
Banner mentions that he's always angry, can transform into the Hulk at will, and implies that the two personalities are more or less on the same wavelength; the World War Hulk arc is built around this.
While Hulk never says "Hulk smash!", or "Puny humans!", his two most famous catch phrases in the comics, both of them are alluded to. Captain America commands Hulk to smash (his exact words being, "and Hulk? Smash."), and Hulk calls Loki a "puny god".
The air-dropped prison intended to kill the Hulk if necessary references the way that Hulk died in the TV show: He fell out of an aircraft as Hulk and landed as Banner.
While discussing the Tesseract, Dr. Selvig claims it will unveil a path to a "new universe".
At the end of the movie, Nick Fury says that all this was a message to the universe: Humans Are Special, defy the odds, and nobody should try to go to war with them. There was a similar premise at the end of Ultimate Extinction. However, the unwanted consequence of this message, attracting the interest of Thanos, is a twist exclusive of the movie
Never Found the Body: Downplayed. Agent Coulsonappears to die, but the scene cuts away before we find out whether he was really Only Mostly Dead and taken to a hospital room. Fury plays the death for all it's worth in getting the bickering heroes to put aside their differences but is explicitly shown to be a Consummate Liar about other things (including lying about the Captain America trading cards being taken from Coulson's body, rather than his locker!). Furthermore, Clark Gregg has said that he was assured by Joss Whedon that the character survives, and is rumored to be in talks to appear in future Marvel movies as that character.
Never Speak Ill of the Dead: In contrast to his teammates, Tony calls Agent Coulson an idiot for trying to take Loki on alone but it quickly becomes clear that this is really just Tony's way of trying to ensure the cracks in his usual snarky facade don't overwhelm him completely.
That scene where Black Widow stands in front of an explosion? It's not in the film. Many alternate takes are used as well.
Coulson never suggests a "time out."
The circumstances surrounding the Hulk catching Iron Man are different from what the trailers would have you believe. It's a case of clever editing. Iron Man's falling because he's out of power after a long fight, ending with his delivering a nuke to the Chitauri control ship, not because he was shot out of the sky. See also Trailers Always Spoil.
The editing would also have you believe that Loki was smirking at the Black Widow when he first escorted into the helicarrier, when in fact he is smiling at Bruce Banner.
Editing suggests Thor laughs at Tony's rebuttal when Captain America asks what use he is without his armor. In the movie, Black Widow is the one shown amused by the response, though it's much more muted. Thor is actually laughing at how "You people are so petty... and tiny."
Tony's delivery of his rebuttal in the trailers is calm and just a little snarky, while in the actual movie it's much quicker and a bit more mean-spirited.
Steve and Tony's curt introduction to each other ("Mr. Stark." "Captain.") occurs not on the Helicarrier when they're out of uniform, but in Stuttgart while they're both suited up.
In the trailer Tony says "Guys, I'm bringing the party to you", but in the movie it's "Then tell him to suit up, I'm bringing the party to you."
Nick Fury's speech is longer in the movie:
Nick Fury: (trailer) There was an idea to bring together a group of remarkable people, so when we needed them, they could fight the battles that we never could. Nick Fury: (movie) There was an idea, Stark knows this, called the Avengers Initiative. The idea was to bring together a group of remarkable people. See if they could become something more. See if they could work together when we needed them to, to fight the battles that we never could. Phil Coulson died still believing in heroes... Well, it's an old fashioned notion.
In the teaser trailer, Fury says, "Gentlemen, you're up." This was actually two separate lines clipped together. In the actual movie, he says, "Gentlemen" when Rogers and Banner first step on to the Helicarrier bridge, and "Captain, you're up" when they find Loki in Germany.
That strange chord that plays when the Leviathan rounds the building chasing Iron Man doesn't play in the film. It's been replaced with a roar.
Newscaster Cameo: MSNBC's Thomas Roberts covers the aftermath of the final battle.
Nice Job Fixing It, Villain: Loki's scheme helps bring the Avengers together, which pays homage to Loki's role in the Avengers comic-book origin, where he brings the team together even more accidentally.
The Nicknamer: Tony calls Loki "Reindeer Games" (because of the horns on his helmet), his scepter "the Glowstick of Destiny" (because of its Mind Control properties and how it glows, and also a reference to the Spear of Destiny), refers to Steve being frozen as a "Capsicle", he calls Thor "Point Break" (because of his long blonde hair, muscles and beard), and Clint Barton "Legolas" (because of his bow and arrow). It is a Joss Whedon movie, after all.
During the massive superhero battle in the middle of Manhattan, no civilian casualties are shown. However, in the aftermath, the news footage includes several shots of people lighting candles and putting up messages on memorial walls. When the Leviathans die, they are shown then crashing to ground and Captain America urges Black Widow to close the portal so the nuclear explosion doesn't come back to Earth.
Joss Whedon didn't want any of the jets to fall off the Helicarrier because that also would be an aversion. He commented that it would kill innocent people, and he didn't want viewers blaming the Avengers or SHIELD for that. Prior to take off workers are shown strapping the jets down, which is Truth in Television for procedure for securing an aircraft exposed to winds that strong that are not intended to experience lift.
Noodle Incident: Black Widow and Hawkeye make numerous references to these from their partnership.
Black Widow: This is just like Budapest all over again. Hawkeye: You and I remember Budapest very differently.
Earlier, in a video file, you see the two in a similar situation, caught between cars and firing in all directions.
No OSHA Compliance: The Helicarrier's angled flight deck leads directly to one of the huge rotors. This means that pilots making use of the flight deck better pray that they land the first time because overshooting will mean getting sucked into a rotor designed to pull the air above it and direct it down with enough force to lift an aircraft carrier. The helicarrier can apparently stay in the air with one of the rotors turned off to make landings safer, but that endangers the entire helicarrier, and leads to uneven wear.
No Party Given: Averted. Senator Boynton, the politician criticizing the Avengers at the end of the movie, is explicitly labeled as a Democrat though if you blink, you miss it.
Thor's lightning is absorbed by Tony's Arc Reactor, charging his suit up to 400% capacity. Neither of them actually saw that coming.
This Might double as a Mythology Gag or Continuity Nod, since in Iron Man 2 it was indicated (in the notes that are briefly shown on screen) that his father developed the Arc Reactor technology from reverse engineering the Tesseract. So, his suit was built as a knock-off of Asgardian technology. . .so Asgardian lightning charging it up actually makes sense.
Loki gets a very unpleasant surprise when his mind-control powers are blocked by Tony's Arc Reactor.
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.
Not the Fall That Kills You: Played straight for the most part, except for one instance where the Hulk rescues a falling Iron Man by sliding down a building to slow his fall, then sliding several hundred yards down the street before finally coming to a stop. He then just drops Iron Man on the ground.
Nuke 'em: Zigzag'ed. The World Security Council's solution to the alien threat is to target Manhattan with a nuclear missile. Nick Fury mentions how monumentally stupid it is. However, Iron Man reappropriates the nuke to strike Chitauri mothership instead, though it wasn't absolutely necessary for victory (Black Widow was about to close the portal.)
Obfuscating Stupidity: Black Widow was introduced during an interrogation with a Russian mobster type who calls her "just another pretty face" while she manipulates information out of him by pretending to be a naive prisoner. She later uses a similar interrogation technique on Loki, playing up her vulnerability until he feels the need to threaten her and reveal something of his plan.
Obvious Stunt Double: Near the start of the film, Black Widow is being awesome. Only, Scarlett Johansson isn't. It's her stunt double, Heidi Moneymaker. Usually, you'd be too enthralled by the fact they're flipping around strapped to a chair, but the change in hair color and the additional muscle makes it a bit obvious.
Occult Blue Eyes: When Loki mind-controls someone, their eyes glow bright blue as an indication (the same color as the gem in Loki's staff and the color of the Tesseract, clues that both use a similar power source), and when released from the mind-control, the eyes turn back to normal.
Odd Friendship: Pretty much any pairing minus Black Widow and Hawkeye, but who does Tony actually get along with first? Banner. It helps that Banner "speaks English".
Natasha's reaction when she realizes that she's been tasked with recruiting The Hulk.
Natasha: Bozhe moi... note Russian for "Oh my God"
When she's pinned down during the attack on the Helicarrier, within a few feet from Banner, and he's changing.
The S.H.I.E.L.D. pilot's reaction when he tries to distract the Hulk by shooting at him with a Gatling gun and the Hulk jumps toward the plane:
Pilot: Target angry! Target angry!!
Tony Stark gets one when the blades of the turbine that he's been pushing start picking up speed, with him briefly getting carried along by one.
Tony: Uh oh.
Tony has a blink and you'll miss it one when Thor starts crushing his gauntlet.
He gets another right after he blasts Loki with the new Mk. VII armor... then sees the portal opening overhead, reminding him that the Chitauri are coming.
Tony: ...Right... (HUD goes into battle mode) ...army...
Thor has a dawning realization of just how much rage Hulk has when he looks Hulk in the eye for the first time.
Tony has a humorous one when Cap is the only one around to fix some some highly advanced equipment. When Tony asks what it's doing, Cap replies, "It seems to be powered by electricity," reminding Tony that Cap is 60 years out of date.
Tony: Well...you're not wrong.
When Banner informs the others that he once tried to commit suicide by sticking a gun in his mouth and "the other guy" spit out the bullet, everyone stares at him in silence as a quasi-godlike alien who spent centuries fighting giant monsters for amusement, a super-soldier used to taking on ridiculous odds, a cocky genius who tried to deliberately provoke him into changing into the Hulk for a laughnote though he also seems sad that the guy he's trying to Bromance is suicidal, and a Magnificent Bastard superspy all suddenly realize what the mild-mannered guy they've pretty much been taking for granted could likely do if he gets annoyed. invoked
Old Soldier: Black Widow is a lot less concerned about the Chitauri than you'd expect from a mundane soldier. She claims she saw worse in Budapest.
Omnidisciplinary Scientist: Bruce Banner is a physicist whose special field is radiation, while Tony Stark is an engineer specializing in weapons, robotics, and electricity generation, yet upon meeting each other for the first time, the two are immediately able to speak (and bond over) the same Techno Babble. Banner was also introduced (in the TV show) as "Physician, Scientist."
Once More with Clarity: Just like in Thor, a Stinger from a previous movie (Thor itself in this case) is fully elaborated here.
One-Man Army: Each of the Avengers is a One-Man Army in their own right, but Tony Stark specifically describes the Hulk as one in the climax.
Tony Stark can spot and identify someone playing Galaga without trying, wears a Black Sabbath T-shirt, hacks speakers to play AC/DC and makes a The Lord of the Rings reference by calling Hawkeye "Legolas".
The usually dry and reserved Agent Coulson turns out to be a huge Captain America fanboy. He even collected the entire vintage set of Captain America trading cards in near-mint condition. He even uses the term "foxing" when describing their condition showing that he's not just a fanboy but a serious collector.
Tony feels this way in-universe about Bruce Banner. Banner being the only one who can understand and speak Techno Babble back to him. There's also this exchange that got cut off in the final edit:
Natasha: You'll love [your lab], doc; it's got all the toys. Banner: Does it have a Commodore 64? Natasha: I'm not sure... Banner: Oh, you're very young.
After Captain America is unmasked during the confrontation at the bank, the camera lingers on a waitress who catches sight of his face. As it turns out, she recognizes him; in a deleted scene we find out that they've met recently.
The Oner: There are a couple of notable ones. Joss is a fan.
On the Helicarrier, half of the blowout between all the Avengers is a single shot, including the upside-down parts. The director's commentary mentions filming it was crazy.
We start with Black Widow riding a hijacked Chitauri craft... to Iron Man covering her back by blasting chasing craft... to Iron Man landing next to Captain America and reflecting his beam off of Cap's shield to clear out enemies... to Hawkeye picking off Chitauri from nearby and far... to Thor and Hulk fighting on top of a Leviathan and ultimately using a concerted effort to bring the monster down. Marvel released this scene to the press to promote the Blu-Ray/DVD edition.
Only a Flesh Wound: Cap gets shot, and later Thor is stabbed, both in the abdomen. They suffer only momentarily since both are wearing armor.
OOC Is Serious Business: Fury and the other Avengers are momentary shocked out of their psychically-induced squabbling when the gentle, easygoing Bruce Banner snarls, "In case you had to kill me. But you can't: I've tried."
Thor is used sparingly compared to the rest of the Avengers. This works nicely — since Loki is the main villain, the film could have risked being Thor 2 if he'd had too much screentime, and his Character Development is mostly shown through body language and facial expressions. It also helps that the extended cast from his movie is inaccessible; Selvig is in enemy hands, Jane is MIA because Natalie Portman was pregnant during filming, and the rest of Asgard are stuck there due to the trashed Bifröst (Thor got to Earth through a far less efficient method due to the emergency). The only person on the Helicarrier he knows is Agent Coulson. He does get a scene with Phil discussing his feelings about Loki targeting Earth.
Also Captain America, even though he has the most screentime, is usually not the focus on whatever scene he is in.
Outdated Outfit: Steve's fashions are hopelessly out of date and what he deems "casual" (long-sleeve collared shirts, maybe with the sleeves rolled up and slacks) seems stuffy and formal compared to Tony and Clint. Cap himself suggests that his old stars-and-stripes uniform is a bit old-fashioned. Coulson doesn't argue, but suggests that with everything that's happened, people "might need a little old-fashioned."
During the prologue, the Tesseract's deactivation leaves a remnant of portal energy, which builds up into a massively destructive blast which implodes the facility and forces everyone to outrace the collapse.
When the Chitauri mothership is destroyed by a nuclear missile, Captain America orders the portal closed to prevent the explosion from coming through to Earth. As the offline Iron Man falls back, not only does he have to get through the portal to come back home, but also to escape the nuclear explosion himself (he makes it with half a second to spare.)
Le Parkour: Cap engages in this when New York becomes a war zone and the streets are littered with cars and debris.
Pass the Popcorn: Loki sitting comfortably to enjoy the fight between Thor and Iron Man.
Pet the Dog: Tony offering to fly Phil Coulson on a private jet to Portland, apparently having overheard his earlier conversation with Pepper where he mentioned that he'd had to break it off with his girlfriend after she'd moved there.
Phrase Catcher: At the climax, when Cap is divvying up tasks. Last up is the Hulk with the exchange mentioned already.
Pillar of Light: As seen on the poster, the Tesseract beam has this look while creating the portal.
Playful Hacker: Tony Stark points out that if SHIELD expects him to be effective, he needs to know everything.
Plot Tailored to the Party: Played with. While there are few obstacles that can be overcome only by a specific superhero, it is unavoidable due to the very nature of the set-up. As Fury points out, the entire idea of the Avengers is to be a versatile and flexible response team.
Pocket Protector: Tony's Arc Reactor performs like this against Loki's brainwashing scepter.
Poisonous Captive: Loki will taunt you and demoralize you and lead his minions to you.
Pop-Cultural Osmosis Failure: Steve doesn't get a lot of references the other characters make. When someone puzzles Thor by mentioning "flying monkeys", Steve's happy that he finally got one. It also goes the other way, when Thor describes an Asgardian beast that Coulson is unfamiliar with.
Tony Stark's kindness towards and acceptance of Bruce Banner/The Hulk, refusing to treat him like a ticking time bomb the way everyone else is, has drastic consequences later on, as not only does his insistence that the Hulk can be used for good get through to Bruce, who decides to come back to help during the final battle, but the Hulk remembers Tony and winds up saving his life.
The Power Of Trust: Between Stark and Banner. In this movie, Stark makes a point of offering Banner trust (even his poke in the stomach can be seen as a demonstration of his confidence in Banner's self control). Banner repays it in spades.
Power Trio: Iron Man fits The Kirk, and Captain America fits The McCoy. Given that Thor is calculative and likes control, and that Banner (when he's not Hulk) is calm and logical, either one could be The Spock.
Props to another Cap and Hulk scene at the beginning of the final battle where Cap asks Bruce how he manages to stay calm.
Captain America: Dr. Banner, now might be a good time to get angry [Banner looks over his shoulder at Cap] Banner: That's my secret Captain, I'm always angry [Banner faces the gargantuan Chitauri ship, simultaneously turns into the Hulk, and stops its onslaught with a single punch]
Captain America gives one to the Hulk near the end of the film as he's giving the other heroes tasks to accomplish.
Captain America: And Hulk... [Hulk turns to face him] Captain America: Smash. [Hulk smirks and leaps towards some Chitauri]
Precision-Guided Boomerang: Both Thor and Cap toss their weapons around with this effect. Thor is justified by it being a magic hammer that he can summon to his hand whenever he wants. Cap is apparently really good at calculating ricochet angles in fractions of a second, for instance when he breaks up the Thor/Iron Man fight by bouncing it off both of their heads.
During the final battle, one of the only buildings with no noticeable damage sports the motto for Farmers Insurance, which all of New York would need by this point.
The Chitauri fly across a clearly placed Dr. Pepper truck, which they blow up along the way.
Tony Stark drives an Acura in this movie instead of the Audis from the Iron Man films. S.H.I.E.L.D. also uses Acura cars, and in a deleted scene, Steve (mulling over his past) walks past a showroom with the Acura RDX 2012 model prominently displayed, along with the company's logo.
Tony Stark's bracelets are Colantotte bracelets, which are supposed to administer magnetic therapy for healthier blood flow. A tie-in comic explains that Pepper bought them for Tony's brithday, and their magnetic properties inspired him to build the Mark VII.
"Does anybody feel like shawarma? I feel some shawarma coming on." was evidently the line that got Nicholas Brendon cast as Xander on Buffy the Vampire Slayer.
Coulson's dying speech to Loki is inverted in an older Whedon production, Angel, at the end of the aptly-titled "Conviction": The villain lectures the hero about a lack of "conviction" to his cause, ensuring that evil will always triumph. Both scenes end in the same way, with the good character silencing the villain with a well-placed shot.
Loki's mind-controlling scepter works by poking people in the heart. It doesn't work on Tony Stark because his arc reactor blocks it. Joss Whedon's earlier work Film/Serenity features a bad guy whose signature move is jamming people's nerves to paralyze them, and a hero with a missing nerve cluster that makes him immune to this.
Prolonged Prologue: The movie begins with The Other explaining to Thanos (and the audience) what their Evil Plan is. Then we cut to Nick Fury arriving at a joint S.H.I.E.L.D./NASA/Project Pegasus research facility being evacuated. Then Loki arrives, takes control of Hawkeye and Dr. Selvig, and escapes with the Tesseract as the entire facility collapses. Finally Coulson asks Fury "What now?" and we get an Answer Cut to the title "The Avengers", a moment made even cooler in the UK release as the title is "Avengers Assemble."
The Chitauri had been told that humans were those but changed their mind after their invasion of New York faced the Avengers and Iron Man nuked their command ship.
Also inverted when the Hulk smashes Loki and calls him a "Puny God".
Pure Energy: When Tony tries to blast the portal generator with his repulsors, they are blocked by a Deflector Shield. Jarvis points out that the repulsors will have no effect, as the shield is made of pure energy.