A bit repetitive but in a nice way. Not that great and not that bad either.

Build an army, then kill the THING at the bottom of the tower.  The gameplay needs to smoothen out the panning of the camera if possible because it is a little slow and the game will depend on the location where the player's army will land. You will have to land on the blue army to add it on your side and fight with the other army protecting the THING.