About 33% of the entire game. If you take the time to read everything, I'd say it comes to around 10 hours of content, give or take.
This game will definitely be longer, yeah. We have made the decision to focus more on character development and story flow. As such, the game works a bit differently as before. You don't have to explore anymore to find the felines. The dialogue trees are longer with more options, and gameplay is more focused on battles rather than mini-games.