How does the super-soldier serum work?
One thing that becomes completely clear as you watch Overlord: This is not a zombie movie. (It's also not a part of the Cloverfield universe as originally rumored.) The monster-like humans shown in the trailer are not conventional zombies that have risen from their graves to feast on brains; these are humans who have been injected with a Nazi-scientist-concocted serum that turns them into ruthless killing machines.
"Even in the development stage and leading to the shooting, we never called them zombies," says Avery. "We always called them super-soldiers. Even though there's a lot of testing and one or two rejects -- and I think we even called one of them 'a mistake' -- they're not trying to create mindless, flesh-eating creatures. They're trying to create an unstoppable army."
Avery compares the research project, which Boyce stumbles onto in the film, to the Manhattan Project. How exactly is the serum, a reddish liquid we see in syringes throughout the film, created? During the scene where Boyce explores the lab, he finds his fellow paratrooper Tibbet (John Magaro) hooked up to a suspicious-looking machine, and while you might think he'll suddenly transform into super-soldier later in the film, he ends up being fine. Was he being harvested? Readied for some other terrifying treatment? Just poked for the hell of it?
"What they're doing is they're preparing to put him in one of those bags, and you see that in the trailer, there's a guy in the bags," explains Avery. "They use the people and put them in the bags, and it's part of the process. They're pumping the people full of stuff, and then stuff comes out of them, and that's the serum. It's kinda like a strange filtration system."
Once the "strange filtration system" process is complete? Voilà, you've got a super-soldier serum.