The most obvious change from the comic book by Mark Millar and Steve McNiven is that last line; the comic book Civil War didn't feature a villain as such, instead it was all about the conflict between two groups of heroes led by Captain America and Iron Man. Many comic fans considered Iron Man the villain of the piece, and he did appear to act the role by creating a homicidal Thor clone and alternate-dimension version of Guantanamo Bay to imprison errant superheroes. Officially, Marvel maintained the line that both sides were morally equivalent.

It should be noted, as well, that the Civil War comic book didn't include an "international incident" of any sort — it was very intentionally a domestic issue, with both sides fighting over the Superhero Registration Act, a piece of legislation that would require authorities to know the identities of (and, ultimately, oversee the activities of) superheroes inside the U.S. following the destruction of a school in Stamford, CT during a superhero fight, which included a group of young heroes called the New Warriors. The world outside of the U.S. didn't really exist in the series, outside of heroes declaring that they'd leave the country rather than sign away their freedom.

There's a lot about that set-up that couldn't work in Marvel's Cinematic Universe, not least of which being the fact that, with the arguable exception of Netflix's Daredevil, the U.S. authorities know the identities of all the superheroes already. In fact, the majority of them have worked for the authorities under SHIELD, with only the Scarlet Witch, Vision and upcoming Ant-Man having avoided the fate of the ones who'll be around for the third Cap movie. (Black Panther, too, but as a foreign national — and head of state — he wouldn't be working for the U.S. government anyway.)

Perhaps the biggest shift between Civil War the comic and Captain America: Civil War the movie is that, while the comic book is entirely centered around the idea of superheroes fighting each other (the tagline for the series, emphasizing the conflict and making it sound like a sporting event, "Which Side Are You On?"), the movie synopsis notably skirts the issue. We're told that "the new status quo fractures," but the team is seemingly still working together to take down Baron Zemo (Daniel Brühl). Should audiences expect more intra-team squabbling, as per the first Avengers, instead of outright fighting?

This doesn't mean that the rumored Iron Man/Cap clash won't come to the fore in the movie, of course — the groundwork for it was laid in Age of Ultron, with Tony choosing a more proactive role than Cap and creating Ultron as a result. But Tony Stark isn't part of the team by the end of the movie, and if he should side with the forces looking for a superhero governing body, he can do so without tearing the team apart.

The themes of the original Civil War comic can remain in place in this new movie version — and it'd be surprising if they didn't, as the "does power corrupt, and can those in power be trusted with what power they have?" themes inherent in Captain America: The Winter Soldier come into play in the original Civil War — but that doesn't mean that the plot will go unchanged. In many ways, Winter Soldier might provide the best model for what to expect: it also shared its title and some plot details with a Marvel comic book, but was very much its own story. (Similarly, Avengers: Age of Ultron had very little in common with the Age of Ultron comic book.)

Whether or not all of this means that the final movie will lack Spider-Man unmasking in front of the country's media is a mystery for another day. After all, the character wasn't even mentioned in today's official cast list… But then, some things work better as surprises down the line.