The actors ensure the script - loose as it is - is adhered to. Audio-visual effects, set design, lighting, costumes and props add to the authenticity.
What if it rains? Director/designer Andrew Foster says much of the show is under cover, but he doubts zombies would respect weather.
The team, which also includes former Weta design special-effects maestro Andrew Beattie, acknowledge the latest zombie zeitgeist comes at just the right time for Apocalypse Z.
"We can give people the real-life experience of what being in a zombie apocalypse - like those they've seen on TV shows like The Walking Dead - might be like," says Van Horn. "I've never grown up, so I still like to play war in the backyard with my friends and I like to play video games. This is like a real-life video game."
London adds that Apocalypse Z's success will depend on the story appealing to audiences.
While they say it isn't for the faint-hearted, they believe it will appeal to gamers and those who want to experience interactive theatre.
Every show could vary wildly, depending on audience responses.
Hackman Theatre's interactive space drama, Apollo 13, which continues to tour New Zealand and overseas four years after its premiere, is the closest Auckland has had to a show like Apocalypse Z.
London and Van Horn acknowledge that Apollo 13 was inspiring. They say Hackman's Kip Chapman encouraged them by telling them to trust their instincts and find creative ways to achieve their goals.
"Kip told us every time they do a run of Apollo 13, they take it to the next level," says Van Horn.
"We're writing our show so it can be played in other cities, so the story can be altered depending on where you are. We'd like it to tour."
If the enthusiasm shown by London, Van Horn and Foster is anything to go by, it means a zombie apocalypse could be coming soon to a town near you.
Performance
What: Apocalypse Z
Where and when: Aotea Square, April 12-27