"I was surprised at how uncompromising Jon was [
in adapting the novel into a screenplay
]. It’s a very difficult character. When you’ve got a difficult character in a book that’s narrating the story, you can put the book down or you can fluff it up in your own mind because when you read a book you’re basically making a movie in your own head.
When you’re sitting in the cinema, you’re prisoner to a director’s vision, so you’ve got to find a way to make a film that’s more instantly approachable, you can’t do something that's going to sort of really turn people away."
"I thought this was one of the best scripts I've ever read. Certainly in the top three. It's an amazing script - so beautifully written. So entertaining, and vibrant, and dynamic and energetic, scary, harrowing, depressing, upsetting and repellant - and yet compelling.
Weirdly as much as it's about this monster, it's about humanity. So there's lots of things. And yet Jon managed to pull it off!"
"The toughest thing was to make Bruce [
] followable because I think in the book he’s darker than the film. He’s less likable in the book than he is the film, so it was really how to make Bruce’s journey something you would care about regardless if you think he’s despicable or whatever.
And also the tapeworm, there was this tapeworm that runs through the middle of the book, but I put that to the side. That was the last thing I included and I managed to do it by personifying the tapeworm through Jim Broadbent’s character the psychiatrist. I concentrated far more on the mental and psychological decline of Bruce in the film, because in the book it’s more a physical decline.
In the film there's a flash of Dr Rossi turning into the tapeworm. In the first draft of the script, there would have been a lot more CGI when he was turning into the tapeworm. How we worked it out in the end, it was just like, subliminal flashes. You just have to get the right temperature in not being too effects-driven because sometimes that can take away the horror of it, you know? Especially in a film like this, it seems a bit too unreal.
It was also difficult finding a narrative because Irvine’s work is great for character and dialogue and it’s so rich that he spoils you with that - so it was a bit difficult to find a straight narrative.”