I've played a few different games like this one. And it's basically a strategic matching tower defense. You can only merge the same units. And they must have the same level. And your only goal is to defeat the waves of enemies before they get to your commander. The ability to play offline is a nice addition, and it's a simple game with advanced quick thinking to outmaneuver the tetris like waves. I'd recommend it to any tower defense, and/or tetris fans.