See also: Luminous' "Backstage" tech demo, and Square Enix of course isn't the only company to do tech demos like that, Unreal likes to do it as well with things like Samaritan (2011) and the recent Unreal Engine 5 tech demo that's unlikely to become an actual game. Quantic Dream's Dark Sorcerer tech demo as well, though Quantic Dream's Kara tech demo did eventually sort of become a game in Detroit: Become Human, but it was definitely not planned at the time.