Marathon's short film director doesn't know why this needs clarifying, but no, he didn't use AI to make it
I won't comment on the quality of Marathon, the game, because I've not had the chance to play it, though obviously it's not been received with all that much fanfare. You know what I did quite like? Marathon, the short film, the one that came with the game's reveal from Alberto Mielgo. It felt like a strong promise of a (more-or-less) fresh sci-fi world, the performances were subdued, it felt larger than life. Good stuff! Yet as many things currently are, it's been scrutinised over potential AI use, prompting Mielgo to put out a (understandably aggro) statement.