the puzzle is ,,, well a puzzle. there's plenty of tricky ones throughout the game. and there's no secret to any of them. They're all solvable. Spend a moment and understand exactly what your and your enemies cards can do. pay attention to the 'rules' of the puzzle. these are sometimes overlooked.

if you're having difficulty with certain battles, its best to come back to them when you're more prepared.

I'll give you one bit of advice. no matter what difficult you play, the battles in this game are fair. any problem or difficulty you face along the way is more of a 'you' problem as far as not understanding your cards strength and weakness, and furthermore not utilizing your army effectively. So understand what your cards and your enemies cards can do, and also the rules of each battle.

It involves a little basic math.

gotta experiment, its quite satisfying when you get it!