How refreshing to see a real in-depth behind-the-scenes special, instead of the 3-minute interview sound-bite compilations that pass for "behind-the-scenes" content most of the time. That was interesting to see, and that dialogue between Gunn and Corenswet over how to play the climactic speech was a potent dramatic climax in its own right. Amazing for something like that to play out before a rolling camera, which is something that you'd only expect to happen in fiction.
I was hoping there'd be some footage of their location filming at Union Terminal here in Cincinnati. I didn't find out they'd been filming here until after it ended, so I missed any chance I had to head down to the Terminal and try to get a look. But there were a few short clips of the Justice Gang confirming that, yes, they did film inside the Terminal atrium, where I've actually been before.
It's weird that they wanted to be authentic by shooting Corenswet lying in the actual freezing snow in Svalbard, Norway, yet had the dog in the scene be 100% CGI. Seems it would've been kinder to let him shoot that scene on fake snow in a warm soundstage, and just send a second-unit crew to shoot background plates in Svalbard.