I don't know. I thought this was fun, but it's a very, very obvious pay to play scheme (meaning it is obvious, even for a game like this).
The energy fills up very slow, you get a free-fill up only all ten levels instead of fe. 5 and now they've even removed the missions were you could earn some kobans.
Sorry, but you need so much energy to get through a single quest and that's in the third country, the girls droprate is horrendously low and there seems to be very little effort put into the writing of the story.
This is a nice idea, but to make me seriously consider spending any money on it, a game has to be better balanced and less of a drag without spending money first.