2013’s Superman reboot Man of Steel is a controversial film in a number of ways. Whereas Christopher Nolan and writer David S. Goyer had previously taken a freshly serious and grounded approach to Batman successfully with The Dark Knight Trilogy, the two were now trying to apply the Batman Begins formula to a Superman story, and it proved difficult. Goyer came up with the core idea for Man of Steel and wrote the screenplay while Nolan helped get the film off the ground as a producer, and then of course Zack Snyder steered the production as the film’s director. At the time, Warner Bros. would neither confirm nor deny if Man of Steel might spawn an MCU-like universe for DC superheroes, but we now know in hindsight it was the beginning of an overall franchise plan that expanded with movies like Batman v Superman: Dawn of Justice and Wonder Woman.

But Man of Steel was a challenging film for some fans, particularly when it comes to its ending. This Superman origin story offers up a “first contact” like twist on Kal-El’s exposure on Earth, and when Superman (Henry Cavill) reveals himself to the world it triggers the arrival of the alien militant Zod (Michael Shannon). The two have a knock-down fight across Metropolis, causing massive amounts of destruction to the city before Superman finally stops Zod by snapping his neck and killing him. Traditionally in the comics, Superman doesn’t kill folks, so this took a number of hardcore fans by surprise.

Henry Cavill in Man of Steel
Image via Warner Bros.

Goyer discussed this controversial decision at length during a Comic-Con@Home panel hosted by Backstory Magazine publisher Jeff Goldsmith. The hourlong interview focuses on Goyer’s approach to adapting comics to the big screen, and the discussion turned to Man of Steel at which point the writer admitted using the “Batman Begins formula” on Superman proved challenging:

“It’s easier to work with a character like Batman realistically than it is with a metahuman from another planet. There’s a higher threshold for suspension of disbelief with Superman than there is with Batman. The attempt with Man of Steel was to apply the same kind of standards, to tell the story of Man of Steel in a fairly realistic way and to try to think about what would happen to the world if a character like that emerged. The entire premise of the movie was that if a character like this emerged from another world who had these kinds of powers, it would be the biggest thing that ever happened in human history.”

Expanding upon that realistic approach, Goyer and the filmmakers approached the ending by wanting to find a stalemate between Superman and Zod – two incredibly powerful aliens – which would then put Superman in a position where he had no choice but to kill his foe:

“We were trying to – if you track the story all the way through in terms of this character emerging and his maturity and fully understanding the kind of power he has, and when they fight the kind of devastation that is caused by it. It’s not some frivolous fight, it’s almost like 9/11 when they fight. We were trying to come up with a stalemate where he couldn’t – there’d been a [comics] editorial decision in which Superman doesn’t kill, it was a rule, but that’s a rule that’s imposed on a fictional world and we just thought but sometimes, whether it’s a soldier or people in law enforcement, and again an immature Superman. This is the first time he’s ever flown in that story. He’d just flown for the first time days before that. He’s not aware of the extent of his powers at all. He’s finding somebody who’s said, ‘I won’t stop,’ who’s said, ‘You can’t put me in a prison I won’t ever stop’. We wanted to put him in a stalemate.”

Michael Shannon in Man of Steel
Image via Warner Bros.

Goyer said the whole idea of Superman killing Zod was borne out of trying to take a big swing, something that had paid off when he and Nolan made Batman Begins and The Dark Knight:

“I absolutely understand a lot of people had problems with it. When I have had a hand in adapting these things, you wanna be as respectful to the core material as possible but you also can’t protect against failure. You have to take big swings. With big swings there are big rewards. We took enormous swings with Batman Begins and with The Dark Knight that turned out to be well-received, but we were trying to tell a different kind of Superman story, a Superman story that hadn’t been told before and it required us taking some big swings. We talked about it. We talked about whether or not people would accept it, and the editorial staff at DC had accepted it. It doesn’t mean it wasn’t a mistake, but if you sit there and you say, ‘I don’t wanna take any risk. I’m worried I might offend a portion of the audience,’ I don’t think that’s a particularly healthy way to try to make a film or a television show.”

The screenwriter recalled a scene that was never filmed between Jonathan and a young Clark that would have further seeded the idea of taking a life, with Goyer noting he’s curious how the film would have been received had that scene been shot and put into the movie:

“Ironically there was a scene we wrote that didn’t get filmed in which Jonathan takes young Clark hunting and they kill a deer, and young Clark is just gutted by the act and Jonathan says, ‘It’s a powerful thing to take a life, even if you’re forced to take a life’. That was a scene that didn’t make it into the final movie, we never filmed it.”

Henry Cavill as Superman looking up and standing proud in Man of Steel
Image via Warner Bros.

There was also a Man of Steel alternate ending that would have given them an out had they not wanted to go through with killing Zod, but Goyer wasn’t a huge fan:

“The idea was that Superman would – there was one of those sort of cryopods on the ship that ends up becoming the Fortress of Solitude that he’s able to put Zod back into and then throw out into space. We did talk about it and maybe some people would’ve been happier with that, but it felt like a cop out for the story that we were telling.”

Indeed, if you’re gonna take a swing as big as Man of Steel overall, go for it. Superman killing Zod isn’t the only major shift to the Superman story in that movie. It’s an entirely different tonal approach than had ever been done before on film, and while some loved it and some hated it, you can’t say Snyder and Goyer and the rest of the filmmaking team didn’t take an ambitious swing.

Goyer added that he views the movies he’s made as “Elseworlds” stories in relation to comic book canon, and with regards to Man of Steel as Superman’s origin story, him killing Zod would be the origin of the “no kill” rule that would endure in films to come:

“I think of the films almost as Elseworlds stories, like Superman Red Son or something like that. To me, the comic books are the comic books and the films that we were involved in are these Elseworlds stories that exist within their own universe. And that was the intention, is that that’s the one. He was in this terrible position and then afterwards he vowed that he could never do it again. It didn’t come out of anger – he was forced into it – but that was the one.”

But Goyer also makes a good point in that canon is a malleable thing nowadays. It only takes one radical approach to change what “canon” means to people:

“Again right or wrong, and I adore the [Richard] Donner film, but this was a new version. Batman and Superman, these other hallowed characters, are constantly being reinvented. And the fact is there isn’t really any real canon. Prior to Alan Moore writing The Killing Joke, Barbara Gordon wasn’t a paraplegic, and then someone else comes along and adds something and that becomes part of the canon and it’s adapted and changed again.”

Even looking at the Marvel Cinematic Universe movies, those films have made significant changes to characters, storylines, and even origin stories from the comics, but they’re immensely popular and well-received. What is canon anyway?

Goyer acknowledges in the interview that Man of Steel didn’t work for some people, and even seems a bit unsure as to whether they made all the right calls in making that film, but again it’s hard not to admire the ambition that went into crafting this fresh spin on Superman.

You can watch the full Q&A below, in which Goyer also makes an impassioned plea for people to social distance and wear masks, as he shares a very personal story of how this pandemic has affected his family. Wear your damn mask, please!

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Adam Chitwood is the Managing Editor for Collider. You can follow him on Twitter @adamchitwood.