Alex Garland has proven many times over that he is great at what he does. The visual style behind Civil War and Warfare feel similar to a style that would work bringing Elden Ring to life. It is hard to adapt a video game in a way that audiences enjoy, but not impossible. I think that choose Garland to be in the director's chair for Elden Ring is a brilliant idea, and so it does not surprise me that A24 has put their faith in him.
