The game is going to be completely free. What you should know is that the upcoming 0.2 version will be exclusive to Patreon until 0.3 comes out and so on. Joining Patreon is a way to support the project, don't feel compromised if you can't afford it and enjoy my game for free.
As for why the game ends at the first fight, it's mainly due to Sena and her personality. Since basically at this point in the story she was out of control due to her growth spurt and she's not a girl you can convince without facts. Anyway, we'll keep thinking about how to improve this part.
And to finish the topic of the starter encounters that I don't like in this game. The girls that are going to fight now seem to me to fulfill the role of combats quite well, but I can reduce their number if there are too many girls.