Most confusing card game on the app store

Ive played a lot of simalar games, but while this one has by far the best artwork, its also ridiculously unintuitive (or just broken).
Case in point: You have to choose a "front line" to attack another player. The game has the option to edit it, but wont save any changes I make to it. Its also difficult to bring up unless youre in the menu to attack another player, and I have no idea how one would set a defensive line. Since a large part of the game involves attacking other players, this has made the game nearly impossible to play.

Raptor2213 about Legend of the Cryptids