The 55-year-old filmmaker has already had discussions with co-writer Shay Hatten about where they could take their zombie heist story next if there's a demand, and Omari Hardwick - who plays Vanderohe - admitted he's had talks with his director about the possibility of bringing back his alter ego.
Zack said: "Look, if there was ever a desire for more Army of the Dead, Shay and I know exactly where the story goes. So, yeah, we're ready."
Omari added to Entertainment Tonight: "There is hope for all of you fans who don't mind looking at Omari's mug, or don't mind following my journey as an actor. There is some hope.
"There definitely have been some talks about the maybes, the maybes and the ifs."
Zack is currently working on an animated prequel series, Army of the Dead: Lost Vegas, which would explain how the zombie plague was sparked and what brought together the Las Vengeance team.
He said: "We're in the middle of making an animated prequel that is adult animation, whatever that is. It dives into the zombies' origins, and we get a sense of what's going on there."
And there's also a second prequel in the works called Army of Thieves, a live-action saga showcasing the background of Matthias Schweighöfer's character, Dieter, which the actor also directed, but that won't be a "zombie movie".
Zack said: "This safecracker story is sort of a romantic comedy heist film.
"It tells where he was before Scott and Cruz find him in the back of Gwendolyn's Locksmith Shop. Ironically, you'll learn that that means something. And the Götterdämmerung [vault] plays an important role in all of this, so that was really fun to do."
Matthias added: "You will be surprised. This will be really funny and entertaining, and you will see heist stuff never seen before... It's before the Army of the Dead, so it is not a zombie movie. But maybe we will see some zombies in that film. I don't know!"