"hesitation" when first tackling the project, fearing they'd fail to deliver that "special sauce".
After many trailers and hands-on previews that hesitation has largely lifted, with only about "one in a 1000" left playing the 'they're not Rocksteady, it won't be any good' card.
Mattes also attributes the immense pressure from Rocksteady's success as likely driving WB Games Montreal even further than they would have otherwise.
"Obviously resistance and reluctance exists at every level," said Ben Mattes. "There were fans who said: 'They're not Rocksteady, they can't make an Arkham game.' And there were concerns within the organisation that we weren't going to be able to deliver the special sauce of a Rocksteady game."
"And there were concerns within our team, like - 'Maybe we've bitten off more than we can chew? Are we sure we're able to dance with these guys? Do we deserve to be in this same hallowed ground?' - but we wouldn't have continued through the years if we didn't feel we had a shot," he added. "I'm really proud of what we've done."
The senior producer recalls a "60-40 split of positivity to hesitation or maybe outright dismay" when Arkham Origins unveiled for the first time to fans of the series, once they learnt Rocksteady wasn't behind it. "Y'know: 'It's not Rocksteady. It's a prequel. It's not the original voice actors. Forget it. Ignore. Never paying attention to it,'" he said.
"But I think every subsequent piece of code we've shown has won over more and more of the public, to the point where it now stands out as an exception if we see someone who's still towing that line of: 'It's not Rocksteady, it's not going to be good.' There's only, like, one in a 1000 it seems now still playing that card."
We now stand on the eve of Batman: Arkham Origins' international release, but the pressure's not off yet.
"You don't want to be the guys who messed up and ran into the ground one of the absolute, top-rated franchises of all time. You don't want that at the top of your CV. 'Yeah, I'm the guy who turned a 96 into a 60, that's my claim to fame.' So I think there was an extra desire to create something really great as we were fully aware of the opportunity that we had."
Mattes is proud of their work with Arkham Origins. "Usually you put on a happy face and say the right things because that's where you are. But secretly you're thinking, 'God, if only they'd given us six more months.' But, honestly, this game we've created is the game we set out to create," he affirmed.
"It is exactly the story we wanted to tell with exactly the areas of focus we aimed to do."
Batman: Arkham Origins also introduces multiplayer into the series for the first time. Let's hope WB Games Montreal has proven themselves both the developer Batman: Arkham fans want and need, and not just saddled with.