It was going to be an MMO. But they are really expensive to make and have small profits margins, and I don’t think it got that far off the ground. I’ve never even seen anything like concept art for it.
Then it got turned into a book series, then that got turned into the TV show, and the game is a game of the TV show. The story in the books is a bit different and no one knows what the story of the MMO was like.