A free program for Android, by Ketchapp.

Crowd defense is an app that will help you strategize on how to defend your location against the waves of the enemy. On how to get stronger weaponry to get rid of the huge crowd that is coming at you. 

In this game, you will learn all about combat, tips, and tricks, and improve and master them to reach higher levels in the game. Each warrior has different damage power and abilities. It is up to you to play defensive or attack. Choose your strategy and beat all enemies. Make sure to win so you can unlock more powerful weapons to clear the huge crowds that come your way.