Interesting, I agree with most of what you said. Except about fast travel, I rarely play games with 2D systems and RPG Maker, so I ran the entire game trying to defeat all the castles, and when I got to the last level I noticed that it was impossible to continue, so I received fast travel and traveled through all the kingdoms clearing all the sidequests and vore scenes, for me, who rushed the game, fast travel at the end was perfect, because if it weren't, I would give up on finishing it, it came at the end when I realized that I needed to travel through the worlds.