Glad you're enjoying the demo so far! Currently, we’ve been thinking about offering both a free and paid version of the game. The free version would be simpler and shorter (for example, no voice acting, no hint system, fewer routes/endings, etc.), whereas the paid version would have more features and extra content.
I hope that's a good compromise! We’d love to make everything free if we could, so that everybody could have the full experience. But at the same time, we really don’t want to go broke, else we won’t be able to make more games in the future. :'D