As the Grand Theft Auto co-writer launches a new project, he reflects on his hugely successful open-world adventures and where game design might go next • Don’t get Pushing Buttons delivered to your inbox? Sign up here As the Grand Theft Auto co-writer launches a new project, he reflects on his hugely successful open-world adventures and where game design might go next Don’t get Pushing Buttons delivered to your inbox? Sign up here I t is hard to think of a more modern entertainment format than