It was never secret that Paramount Pictures’ summer blockbuster World War Z was troubled. The battles between producer/star Brad Pitt and director Marc Forster were very public, and the millions spent on shooting a different ending was well documented. Still, the movie was a monstrous success, and a sequel is now in development, so why not open up about the presumably stressful zombie epic?

Empire gets major props for getting Forster to address the elephant in the room and open up about the drama, explaining the reasons for changing the film’s finale.

“Basically, originally there was a third act that I thought didn’t work,” he explained. “As we were shooting we were discussing it and rewriting and rewriting it.”

Explains the site, in common with Max Brooks’ source novel, the third act was due to take Brad Pitt and a small army of zombie killers to Moscow for a final pitched battle. But a change of heart moved the action 1000 or so miles due west for a more intimate Wales-set ending: “The reason I felt it wouldn’t work is that by that time you have a certain battle fatigue after Israel. After Israel and the plane crash, trying to trump that and make it even bigger wasn’t working in our favor. The problem with a lot of these big movies is you start production and the script isn’t finished. The third act wasn’t fully fleshed out, but we had to rush in to meet the release date.“

If you were hoping to see the original ending, there’s a reason it’s not on the home video releases – the effects work was never completely. Instead, the money was used to reshoot the ending entirely. “I was very happy that we didn’t finish the third act with visual effects and everything,” said Forster, “because that would’ve been a huge number, and we used that money to shoot a much simpler ending.”

The ending was definitely simpler, but it also felt like a massive step backwards from the insane action that proceeds it. It’s actually one of the main reasons I didn’t love the movie. Still, I admire what he’s saying about “fatigue” – it’s difficult to watch a non-stop assault for two straight hours. And even if it didn’t work well, in some ways I think he made a very justifiable and smart decision.