After about a week on the internet, the trailer for Avengers: Infinity War is already at over 87 million views on Youtube alone - making it the 2nd highest viewed movie trailer of all-time (behind The Force Awakens) and - by far - the most viewed movie trailer for any film in the Marvel Cinematic Universe. What might surprise you is the trailer it overtook - the original teaser trailer for Age of Ultron:
Given the general consensus around Age of Ultron (which is...not great), it might seem odd to think back to this - but there was a time when Age of Ultron truly looked like a big, bold step forward for the MCU - and this trailer was a big reason for that. Why was this trailer so great, though?
Let's get this one out of the way first: James Spader's voice is absolutely perfect for this kind of role. It's ominous, full of personality, and gives a good sense that he could commit mass human genocide and you would still think he was pretty cool. The whole idea of giving Ultron moving facial expressions (aka "Ultron lips") seems like such an unnecessary step given Spader's voicework is more than capable of conveying everything you need to know about Ultron. His growly "I'm gonna show you something beautiful..." sets the apocalyptic tone of the trailer perfectly - you're terrified of this voice before you have any idea who it even belongs to.
In the actual movie: Of course, he's a BIT QUIPPIER and SNARKIER and overall MUCH MORE TONY STARK-Y than ominous threatening robo-Spader. Oh well, I guess Robot California isn't the worst thing.
By the time we finally see Ultron in the trailer, we're prepared to be scared of this guy - the combination of James Spader's voice, his monologue about making people scream for mercy and his takedown of what the Avengers represent, and the general imagery of chaos and confusion lead us to believe this guy is something formidable. And then...he's a broken down robot, barely capable of dragging it's fractured body across the floor. He looks weak and incapable of doing any harm to Earth's Mightiest Heroes - and yet the fact that he's so utterly confident while staring down the Avengers makes him even more frightening.
He doesn't need lips to make us terrified of him.
In the actual movie: This body didn't last too long - he almost instantly upgrades to lips and ditches the frozen-faced Ultron we had known all our lives. Oh well.
The nice thing about Ultron (in this trailer, anyways) is that he manages to have an actually valid, interesting reason for hating the Avengers, and one that's summarized in only a few sentences. While other villains hate the Avengers simply because they keep getting in the way of their world domination schemes (Loki, Thanos, Pierce) or out of personal petty vengeance (Zemo, Killian), Ultron sees a much more fundamental flaw in the Avengers: they're here to protect the status quo. And while the status quo works out well for some people, there are PLENTY of people regularly screwed over by the current way things work - and the Avengers won't do anything to solve those issues.
We know massive levels of poverty and oppression exist in the Earth of the MCU - Sokovia is a failed state filled with destitute people, North Korea still exists as a closed-off dictatorial state (implied in Iron Man 2), etc. The Avengers aren't going out and righting injustice in the world - they're there to fend off otherworldly attacks and not much else. So what's the point of having a superpowered team of do-gooders (who, at this point, aren't tied to any government) if they won't do more to fix what is glaringly wrong with the world?
Of course, the movie digs into that a little deeper - but it's a pretty interesting motivation for this big mean robot.
In the actual movie: Uh, his plan is to throw a city at the ground to cause an extinction-level event to destroy humanity in order to "save Earth" is a pretty stock villain scheme.
Okay - the "children's choir singing a happy song in a sinister tone" is a well-worn cliche at this point, but Age of Ultron might be the last trailer to use it well. Implying the sequel to the biggest superhero movie ever stars a messed-up, evil version of Pinocchio is pretty cool, purely based on what a batshit idea that sounds like actually typing it out. "So how are you going to top one of the biggest movies ever made, Joss Whedon and Kevin Feige? Oh, by adding EVIL PINOCCHIO, of course."
But if it were JUST that ominous kids' choir, it would feel pretty cliche and pointless...but ending it by having James Spader in a brand-new robo-body step in and say the final lines ("I'm free....there are no strings on me.") really sells it - by adding in the implication that (up until this point) he's been bound by strings holding him back (and was still infinitely frightening) and that now he was finally able to let loose.
In the actual movie: Of course, we then found out Jarvis had somehow managed to prevent Ultron from accessing the internet EVER somehow? From every location on Earth? And also stopped Ultron from just uploading his consciousness onto a couple thumb drives or something JUST IN CASE? C'mon, evil Pinocchio, you should try a little harder.
As far as setpiece teasers go, it's really hard to imagine ever topping the first glance we had ever gotten of a MEGA-BUDGET HULK VS. HULKBUSTER FIGHT. Sure, the team had sparred a bit with the Hulk in the first Avengers, but it was mostly Black Widow running away and Thor getting a few good licks in, and all of that was limited to the dull environment of the SHIELD Helicarrier. What Age of Ultron promised was the introduction of Stark's Hulkbuster armor - capable of allowing the de facto main character of the MCU to go toe-to-toe with Hulk. Why were they fighting? What city were they in? Why was the Hulkbuster armor floating onto Tony in pieces? It didn't matter. It was a real, onscreen Hulkbuster fight, and that was all that mattered.
In the actual movie: Well, by the time the movie came out, the entire sequence had been previewed and teased out so completely that every viewer had basically already seen the entire thing in-full.