Hi! I have played the game for almost 2 weeks now. I may be very subjective since I will speak from my experience. It still has many error especially the crashing of the game. I have seen many reviews from the playstore giving it low stars due to its difficulty but from my experience I also thought of that but turns out I just missed the ways to enchance my EP, there are many ways to enchance EP: Upgrading equipments and evolving them, max leveling characters, Maxing the ability release of the characters being used along with the supports they are with, and upgrading skills. Also, perfecting each stage is a bit impossible depending on each player's characters but just finishing them is enough. You could always comeback to the stages you couldn't perfect but staying in a stage just because you couldn't perfect it will hinder you from getting more population which is a must. Staying stuck in a population also means getting stuck in a certain amount of EP so no need to be frustrated in each level. You could finish it after getting a certain amount of EP or character.
That's all I have to say since in the google playstore it had a maximum of 500 character, I had to write my tips here. This app is very convenient. I like it.