Saito-san mentioned that during previous interviews at Gamescom he answered that the game would last about 25 hours, but when he told that to the staff back in Japan they said no, it probably takes a lot longer than that.”
He also explained that you dont need to do the side quests to clear the game and reach the ending, but there are multiple endings, so if you want to see the true one, youll probably have to do the side quests as well.
There are short side-quests with stand-alone objective that ask you to find an item or similar simple objectives, but there are also longer side quests that might have several chapters telling a longer story.
It's a short blurb, not even really a full article, but basically they did a short interview with Yosuke Saito and they fully confirmed that this game isn't just Revengeance with Yoko Taro, like some people on this forum have said it is. It's an action RPG with towns and quests and everything.
Site is banned so I won't link it.