This is NOT a strategy game, but a game of luck. You can't pick piece of your choice. Most of the time, high-cost troops come in your crate at the very beginning. They takes so long to charge that by then you have lost half the battle. It's a game of LUCK like Poker(which card u get 1st, which opens next, and so on), not a game of a strategy like "chess" or "plant vs zombies", where you can freely use a piece from all the available pieces. ABSOLUTELY FRUSTRATING.