First of all, the fact that Marvel caved in and put the trailer up a week before it was originally due for release. And then showing additional footage on the day that the original trailer was supposed to air.
The debut of the Hulkbuster Armor, truly living up to its name by going up against Hulk... And, as seen in the actual movie, winning... Including this clip... Bonus points for Tony finally getting the modular armor concept working properly, which was a far cry from the glitch-heavy Mark 42 armor in which said feature was tested with mixed results.
"You're all puppets! Tangled in...strings." [seizes damaged Iron Drone by the head] "Strings." [crush]
A sneak peek shown at Comic Con and after an episode of Agents of S.H.I.E.L.D. (before Ultron shows up and everything gets serious) shows the Avengers having a little get-together and a contest on who could lift Thor's hammer. While no one else is able to move it at all, Steve manages to budge it a bit, which makes sense considering his comic-known worthiness. The realization that Steve might actually pull it off induces an Oh, Crap! from Thor.
This scene's payoff would come in Avengers: Endgame, when yes, Steve is worthy of the hammer. And uses it to devastating effect.
Word of God even confirms that Steve was just pretending not to, to let Thor have his ego boost... He's nice like that.
Steve is arguing with Tony while they chop wood. At one point, Steve gets angry enough to rip open a log (completely in half as though it were paper) with his bare hands.
More undersated, but note Tony's reaction to this. Rather than look shocked or surprised, he just glances at the results of Steve's outburst as if to say "do you feel better now?"
Quicksilver smashing a drone with super speed is nothing short of awesome. Even better in the finished film: it's not a drone, it's Ultron himself.
As Cap throws his shield, Quicksilver dashes in to deliver an uppercut to his chin before the shield returns to his hand.
Black Widow scooping up Cap's shield as she passes on her motorcycle. The final trailer shows that after scooping it up she catches up to the truck where Cap and Ultron are fighting on top of, slides under it on her bike and throws the shield up to Cap who catches it magnetically with his gauntlet.
Upon the release of the 3rd trailer, there came a scene where all of the six heroes jumped all together in a fight against HYDRA.
The very end of the third trailer shows a shot of Vision opening his eyes.
The TV Spot gives us:
Captain America riding his motorcycle, flipping forward and throwing it onto an oncoming jeep full of HYDRA agents, wrecking their vehicle. And then admitting that he just slipped.
Black Widow approaching the Hulk without fear, especially considering that encounter in the last film.
Cap kicking up his shield and Thor using his hammer to hit it at oncoming Ultron drones.
Thor: It's all in the swing.
Hawkeye saying, presumably to Scarlet Witch:
Hawkeye: If you step out that door, you're an Avenger.
As much as fans love Black Widow, Scarlet Witch's introduction is much appreciated. It means there will finally be a superpowered female lead in the MCU, and help expand the team's diversity before Captain Marvel is released.
Thor and Cap's Combination Attack . Thor hits Cap's shield with Mjölnir, creating a shockwave strong enough to make the HYDRA goons blow up like bowling pins. Bonus points for finally using that move after teasing the fans with the forest scene in the first movie
Creepy Awesome Wanda and the fact that she has taken out nearly all the Avengers with her mental powers, culminating in taking control of the Hulk! A truly villainous CMOA.
The one-shot scene like in the first movie. In the first movie, that scene was a big, expensive, complicated effects shot that they nearly gave up on multiple times; Whedon persevered, saying that something like that was the whole point of making an Avengers movie in the first place, and it serves as a big "payoff" scene for the audience. In this movie it's the opening scene.
It also manages to one-up the previous movie by having a slow-mo ramp shot of all six Avengers lunging into battle. Not only does it perfectly encapsulate the two-page-spread of the comics, it adds an element of exhilaration to the film: the filmmakers are showing off how much they've got a handle on things.
During a lull in the opening battle, Thor and Steve regroup and agree that their best bet would be to have Thor fly an injured Clint onto the Quinjet, while Steve and Tony secure the scepter. However, a group of Strucker's soldiers choose that exact moment to ambush them. Cue Steve and Thor pulling a Call-Back to the first film, with Thor bringing Mjolnir down as hard as he can on Steve's shield, which causes a sonic boom that knocks every other man in the field flat on their back.
Thor: Looks like they're lining up.
Steve:[holds up his shield with a slight smirk] Well, they're excited.
Steve cornering Strucker. When the Baron still insists on taunting him, Steve—who'd just been knocked down a flight of stairs, courtesy of Wanda—promptly kicks his discarded shield up and into Strucker's gut. Cue Strucker landing on the floor in a whimpering heap.
The payoff to the hammer-lifting contest from the trailers. In the middle of a debate as to whether he can be trusted, the Vision shuts the whole thing down without even trying... by casually handing Mjölnir to Thor. The second time he lifts Mjölnir, he full-on smacks Ultron in the face with it. Afterwards, he takes the time to compliment Thor on how well-balanced it is.
Although Steve manages to move the hammer a little bit, which takes Thor by surprise. Not as awesome as the comic where he could lift it with next to no problem, but it still puts him ahead of the other Avengers.
Quicksilver intercepting the arrows Hawkeye was firing at a HYDRA bunker, and then making Cap and Hawkeye look like idiots.
During the Ultron drones attack, Tony shows once again that he is not defenseless without the suit by taking out an Ultron drone with nothing but a kitchen knife, before doing a flying leap off the balcony armed with nothing but his trusty screwdriver to take out another.
Just before that, an Ultron drone punches him through a bookcase. The above is what he does in response.
Scarlet Witch takes out the Avengers one by one... until she gets to Hawkeye, who has had quite enough of people messing with his mind, thank you very much.
Hawkeye: (after striking Wanda with an electric arrow) I've done the whole "mind-control" thing. Not a fan.
There's also Tony breaking out of her illusion all by himself earlier. This cannot be understated - neither Thor, Cap, the super spy Natasha, or the goddamned Hulk could break free of her visions, but Tony, someone with zero mental conditioning compared to the previously mentioned individuals (who've all had a bit of military indoctrination in their careers) manages to shake it off. Made even sweeter by the Oh, Crap! face Wanda has when it happens.
Ultron's dramatic introduction to Wanda and Pietro. While Wanda snarks that every man shows himself sooner or later, Ultron stands and she immediately gets an Oh, Crap! look as he faces them.
The entire Iron Man vs. Hulk fight. Remembering how easily it went down in World War Hulk, it was a joy seeing the Hulkbuster actually being effective. And it even wins. What makes it even better is that whenever it becomes a contest of brute strength, till nearing the end of the fight, the Hulkbuster managed to match the Hulk pound for pound. And pulling out every move in the book including several wrestling moves so that the Hulk almost never gets the chance to use his strength effectively, added with the fact that the limbs can rotate and strike at all angles! The fight ends with Iron Man pulling the mother of all meteor moves, throwing the Hulk into a half-built skyscraper, firing missiles after him, then ramming him through the whole thing. And then sucker-punching him into unconsciousness when the Hulk manages to pull himself out of the rubble. This can be credited to Banner having been involved in the design process this time around. And through the whole fight, against a foe who inspires mortal terror in the hardest of men, Tony is snarking his ass off. Whatever the man's nerves are made of, if he found a way to make a suit out of it he'd be able to take on the world.
This actually makes a good deal of sense considering Banner's involvement. Tony would have built the suit to contain his best friend; Banner would have made it to put his worst enemy down.
Also, before the fight, the Hulk is temporarily trapped inside a special high-tech cage that he actually can't tear apart; so, to escape, instead of trying to break out of the cage, he improvises an underground tunnel by hitting the ground, showing once again that he's much, much more than just brute force.
Even better was that Tony knew that it was a battle of time. While the Hulkbuster could fight on even terms with the Hulk, the Hulk gets stronger the angrier it gets. Plus the Hulk was constantly damaging the Hulkbuster unit, meaning he wouldn't be able to hold out for long. He needed to stop him as fast as possible and did everything he could to make sure that happened. Throughout the entire fight, Tony knocks him down only to get back up a second later and go harder. Tony had a fight against the clock and won, but only with a sneak attack.
It gets even better because right before the Hulk gets really angry, the Hulkbuster clocks him with an elevator car, followed by a roundhouse punch so hard that it makes the Hulk faceplant and spit out a tooth. Considering Banner once claimed that the Hulk spat out a bullet he had tried to eat, it says something that Tony was able to physically damage him.
The very idea of having a machine that sends him spare parts as soon as the armor gets damaged.
One for the Hulk and Iron Man. In the middle of the fight, Iron Man pins the Hulk and activates a jackhammer mechanism in one of the Hulkbuster arms, pummeling the Hulk repeatedly ... until the Hulk has enough, grabs the jackhammer arm, and crushes it.
A comment on the comics example used: the Hulkbuster in World War Hulk was something Stark quickly put together, not for outpunching the Hulk but as a delivery system for a nano-serum intended to sap the Hulk out of his transformation. The original Hulkbuster modular armor was actually pretty effective, and like in the movie, it allowed Stark to hold his own against the Hulk. Even better, the Hulk even had to talk his way out of that fight.
Captain America fighting Ultron on top of the truck carrying Vision's body. Cap himself admits he has no chance against Ultron, but manages to hold his own for an improbably long time.
To give a much-needed elaboration, Cap fights Ultron for a good four minutes (in movie time) evenly, managing to contend with a robot many times stronger, faster and more durable both with and without his shield. Ultron throws him from the truck? He uses Le Parkour to get right back up there in less than a minute. Ultron using his pseudo-telekinesis to hurl cars and rip up the street at him? Cap keeps up while sprinting before riding an upended wrecked car in snowboard fashion to take the fight back to him. He needs to get Ultron off the truck for the team's extraction? Drive him through the side of a train via flying tackle, of course! The fight only ended in that Ultron managed to get Steve against a wall and begin furiously pounding at him. If not for that stroke of luck, it seemed Cap could have contended even longer. All in all, this is a much more dignified bout for him than he got against Loki.
The most impressive thing about this fight is this. Cap couldn't beat Ultron. Ultron couldn't knock Cap down without his blasters unless Cap didn't have his shield.
Even better, the subsequent Agents of S.H.I.E.L.D. episode reveals that Coulson stored and maintained that Hellicarrier for quite a while prior to this event. Score one for the new director of S.H.I.E.L.D.!
The Ultron drones immediately fly after them, only for War Machine to suddenly appear and gun them down mid-flight.
If your eyes and ears are both on Rhodey, you'll notice that he gives one Ultron sentry an open-handed face full of repulsor.
Ultron only has to reach his device to make the whole city fall on Earth causing massive casualties.AnyUltron. With only the Avengers standing between all the droids and the device, he taunts them asking how they plan to stop him. Tony just answers "together". Cue the showdown with the Avengers trashing dozens and dozens of Ultron as they come, culminating in the Vision, Thor and Iron Man hitting the main one together, stopping it, and the Hulk sends it flying for good measure. Also Ultron Prime surviving that.
Quicksilver destroying so many Ultron bots while being a human harpoon armed with nothing but Super Speed and Good Old Fisticuffs is nothing short of awesome.
A very subtle one; at the party Thor warns the veterans that his Asgardian drink can't be handled by "mere mortals". He then promptly pours Steve a shot without hesitation and hands it to him.
Not to be outdone, one old vet points out that mere mortals couldn't survive Normandy either, and they each hold up their glasses to get a taste of the stuff. And this WWII vet is played by Stan frickin' Lee! Especially awesome considering how Stan Lee, Jack Kirby and other legendary comic creators really did serve in the military.
Short as it is, the stinger is one: A grinning Thanos picking up the Infinity Gauntlet, finally taking matters into his own hands. He even sounds excited at taking on the Avengers himself.
Thanos: Fine, I'll do it myself.
Seeing the whole new Avengers lineup assemble. It's neat to see The Vision, War Machine, Scarlet Witch and The Falcon officially become a part of Earth's mightiest heroes, even while you know Iron Man, Thor and Hawkeye can always come back when they feel like it, as in the comics.
Who gets to finish Ultimate Ultron in the end? Righteous and pure Steve Rogers vs. the cynical fatalist? Tony Stark destroying his deadliest creation? The Black Widow slipping past all the flashier Avengers and hitting Ultron from behind? Actually it's Wanda, the young woman that was terrified of fighting drones not that long ago.
Ultron: If you stay here, you'll die.
Wanda: I just did. Do you know how it felt? [rips out Ultron's heart like it's made of tin.] It felt like that.
Keep in mind that at this point, Ultron is made of vibranium, an alloy strong enough to withstand Thor's hammer.
The end credits sequence showing a really cool-looking marble sculpture of all The Avengers (the old and the new) in action against Ultron.
Hawkeye talking to a terrified and overwhelmed Wanda, telling her he understands if she cannot keep fighting, and that it's okay, and he even forgives her for what she's done in the past. But if she's willing to stand up and fight, she's one of them, no matter what.
Hawkeye: Are you up for this? Are you? Look, I just need to know, because the city is flying. Okay? The city is flying, we're fighting an army of robots...and I have a bow and arrow. None of this makes sense. But I'm going back out there because it's my job, okay? And I can't do my job and babysit. It doesn't matter what you did, or who you were. If you go out there, you fight, and you fight to kill. Stay in here, you're good; I'll send your brother to come find you, but if you step out that door...you are an Avenger.
A couple of minutes later, as Hawkeye is getting surrounded by Ultron drones, she does. Wanda comes out the door and begins literally ripping apart drones with no effort. Even before the pep talk from Hawkeye, Wanda did a very good job fighting the drones and protecting the civilians as she led them to safety, while visibly shaken up in the combat.
And then later when Wanda offers to guard the device singlehandedly. She punctuates this by grabbing a drone who's rushing it at full speed, crushing it like a tin can, and throwing it clear out of the cathedral.
Helen Cho of all people gets a couple, albeit small: she enters her lab to find Ultron awaiting for her, who threatens to kill her and all of her associates should she scream, and Helen is only mildly scared— she manages to maintain some amount of composure. In fact, she even snarks at Ultron when he praises her for the information he acquired from her to achieve his goals.
Helen: A thank you notice would've been nice.
The second time is in tandem with Wanda, who after realizing Ultron's true motives, flicks her hand to free Helen of her brainwashing. The second that happened, Helen immediately assessed the severity of the situation and shut down the project creating Vision despite knowing how doing so would get her killed by Ultron. Fortunately, she manages to survive being almost killed by Ultron (likely because she was in her own lab), and at the end is seen working at the Avengers' new headquarters in Upstate New York.
Vision vs. Ultron. Vision descends from on high (a la Superman) and Ultron meets him in the air. After exchanging some words, Vision manages to grab hold of Ultron's head and burns him out of the internet, trapping him in his now-finite number of drones. On top of that, Vision also gets to finish off Ultron once and for all when the latter finds one last drone body to inhabit.
Ultron: You are...unbearably naïve. Vision: Well...I was born yesterday. Ultron lunges at Vision and gets erased.
Everything Klaue does. When Pietro and Wanda show up to intimidate him, he quickly and preemptively stops their tactics, chews them out, and offers them candy. He even takes losing part of an arm well enough, being coherent enough to give orders to his men afterward.
The skirmish in Seoul. Ultron and Captain America's battle takes them both into a train full of people. With limited space to fight properly, Captain America is at the mercy of Ultron until HeelFace Turn Quicksilver and Scarlet Witch save him. Unfortunately, the train driver gets killed in the ensuing fight, and the now out-of-control train runs off the track. Cap immediately shows that he's still a great leader by calmly ordering Quicksilver to get any civilians out of the train's path and Scarlet Witch to use her powers to bring the train to a stop. Kudos to the Maximoff twins, too, for knowing their roles and acting upon them with no hesitation despite being ordered to do so by a person who for all they care was one of their enemies just two seconds ago.
As mentioned in the pre-release section, Natasha's bike chase prior to that moment where she delivers Cap his shield. But what she does after that point is pretty awesome too: slipping past Ultron into the truck carrying Vision's casket and escaping with the "package" by jumping out of the about-to-explode truck while it is flying in midair into the back of the Quinjet. Granted, she gets snatched away mid-air by Ultron, but thanks to her the casket ends up in the Avengers' hands.
While a few have been noted, everything Hawkeye does in the film. He's the only one able to beat the Maximoff twins, showcases his aiming skills effectively, as well as being able to stand his ground as a core character in the film, given how minor he was in the previous film. There's also something pretty cool about the one guy who has no powers or suits of armour being the only one with a fulfilled civilian life.
Not only that - Clint Barton is, for all intents and purposes, the most well-adjusted and grounded person on the team. He's run into a lot of weird things during his tenure with S.H.I.E.L.D. and just takes it all in stride. Being around super soldiers, gods, and mad scientists barely even hurts his pride and he has no problem keeping up. When the team takes a hit, he opens up his home, introduces them to his family, and helps them get back on their feet. He's not just the man— he's the big brother.
Thor and Iron Man working together to destroy the city by by having Iron Man create an energy seal around the vibranium core that will concentrate all the power Thor will hit the core with. The resulting explosion vaporizes most of the city.
Gotta give the last remaining Ultron drone credit for pushing that button after how much damage it took.
Thor surviving the explosion of the city despite being at the ground zero, and for Iron Man who shrugged off the explosion while being at the outer edge and the vibranium core collapsing on him.
Natasha planting The Big Damn Kiss on Bruce, then promptly shoving him off a cliff because she needed the Hulk to get her back in the fight. Doubly so because it shows Natasha has overcome the fears and doubts sparked by Wanda's visions, as by doing so she chooses being an Avenger over running away with Bruce like she'd wanted to earlier.
Natasha using Cap's shield to fight the Ultron drones.
Natasha rigging a communication device to signal her location to the Avengers after Ultron kidnaps her, letting them know Ultron is back in Sokovia.
Ultron has used the remaining Vibranium to build himself a virtually invincible primary body. Even smashes from Mjölnir merely send him flying, with no lasting damage. As they're defending the core from him and his drones, Thor, Iron Man, and Vision all fire their beams/lightning at Ultron Prime simultaneously. As Ultron pushes against the beam for a while, eventually the awesome Avengers theme kicks in as his indestructible Vibranium body finally begins to flake apart and melt, and the look on Ultron's face says it all. Even though it's still quite a while before he's down for good, it does mark the beginning of the end for him, and the massive uppercut-out-of-the-screen from Hulk immediately after doesn't help his cause either.
Ultron, being the idiot that he is, after the above, despite being too damaged to fight straight-up steals the Avengers Quinjet and starts firing on the Avengers. The minigun bullets just bounce off Thor and Hulk, Cap and Widow just move out of the way, though he manages to kill Quicksilver. Then he tries to escape, only for Hulk to chase him down, leap onto the Quinjet, beat the stuffing out of him and throw him out in 3 seconds flat. This renders Ultron completely defenseless and unable to move, leaving him ripe for Wanda to finish. And if you pay close attention, Hulk has dented the left side of his face, which as mentioned before is made of vibranium.
Fury and Hill get to show once again why they were so high up in S.H.I.E.L.D. when a drone breaks through War Machine's defense line. The drone crashes into the bridge and once again Hill and Fury are the only things protecting the bridge, the latter empties her sidearm into it while the former stabs the drone with a huge shard of metal until it stops moving.
You've gotta give some credit to the Sokovian police force. The city is being attacked by robots and is flying mid-air, with civilians in danger everywhere, and they're just doing their jobs the best they can, not giving into their fear like the civilians because those same civilians need protection and the Avengers need help. Then when the city is evacuated, they take charge while the Avengers are busy fighting off the bots, getting everyone to safety, and are among the last to leave.
A partially off-screen moment of awesome. It's mentioned early on in the movie, that Ultron is probably taking lessons from the Terminator series, and is likely trying to crack into the world's militaries' nuclear arsenals. Fury, while the heroes are recouping at the Barton family farm, confirms that Ultron is indeed doing this. Matter of fact, he's been constantly attacking ALL of the military networks, trying to get the launch codes, but someone, no one knows who, is keeping the codes on a constantly rotating cipher to lock him out. Tony goes to find out who, using his hacking skills to bait the one responsible out into the open. Turns out, it was J.A.R.V.I.S., who also pulled a similar trick to Ultron, uploading enough of his program onto the net and doing whatever he could to slow down Ultron's plans.
No love for JARVIS? While not as immediately awesome as some of the above examples, JARVIS is a relatively simple Virtual Intelligence. His code likely consists of "If this, then do that". In the early parts of the movie when Ultron FIRST came online, JARVIS defended the Avenger's Tower network as best he could while simultaneously uploading himself into the Internet without Ultron even realizing it. JARVIS then spends the rest of the film using guerrilla tactics to keep Ultron from accessing nuclear launch codes or other extremely important information via the Internet. All of this was before the Infinity Stone gave him true intelligence and transformed him into The Vision. JARVIS was kicking ass before he became The Vision! And when you think that JARVIS sacrificed himself trying to stop Ultron in the beginning, and then kept on fighting back for weeks afterwards, you better believe he's worthy of wielding Mjölnir!
Wanda with her powers compelled Bruce to lash out as the Hulk, destroy an African city, injure multiple civilians, and nearly earn an arrest warrant. Given how scared Bruce is of this happening, the fact that he only tells her post HeelFace Turn that he doesn't have to turn "green" to snap her neck before accepting her help shows much physical restraint. Bruce understands The Needs of the Many far outweighs any legitimate grievances. Props to Wanda as well for not raising an eyebrow at the threat and helping the team despite having performed Mind Rape on most of them.
Then during the fight over Vision activating, Bruce grabs Wanda in a chokehold and says "Go ahead, piss me off."
Then when she does blast him, instead of Hulking Out he is now able to hold back the transformation, showing his control over the transformation has indeed increased.
Cap's speech as the Avengers prepare to leave for Sokovia. He makes their mission statement perfectly clear: they're not just out to beat Ultron, they're out to prove him wrong. Ultron's spent the entire movie criticising the Avengers for being, in his view, what's wrong with the world, so they respond by showing him why they're heroes by refusing to leave Sokovia until every single civilian is evacuated. And they succeed, shutting down every one of Ultron's Breaking Speeches.
Captain America: The rest of us have one job: tear these things apart. You get hurt? Hurt 'em back. You get killed? Walk it off.
A recent incomplete deleted scene shows Vision's birth going a little differently. Originally there was to be a fight between Thor, Iron Man and Captain America against the creation freaking out a little. While a little jarring on the character level, it immediately showcases The Vision as being an absolute powerhouse.
Vision's actual creation is awesome in its own right. In the middle of what looks to be Civil War come early with Tony and Bruce facing Steve and Wanda, Thor smashes through a window into the room and, without saying a single word or even acknowledging anyone in the room, proceeds to call down a massive bolt of lightning indoors and bring Vision to life.
Cap pulls of the same later when a drone tries to sneak up on him during Ultron's Evil Gloating, but uses his fist instead.
A blink-and-you'll-miss-it moment which shows the great synergy of the team. During the fight with the Ultron horde for the machine, an Ultron drone almost blindsides Cap, who Cap notices coming towards him only a second before and having no time to counter or block, he swiftly jumps straight up six feet into the air from a standing position. The Ultron drone immediately turns around to blast Cap, and on cue Vision flies in and puts the drone in a full nelson, and immediately Iron Man arrives and repulsors the drone to kingdom come. Mind you, all this took place before Cap even hits the ground.
Black Widow taking down a Ultron drone with her signature hurricana.
Props to the four lifeboat pilots: Flying unarmed rescue vehicles into an active war zone, having to trust the superpowered heroes to keep the Ultron drones from blowing you, and your charges, out of the sky!! Nerves of steel, those pilots!!