Evolution

From my research i have seen that within most tower defense games you get unlocks that mean you can defend the tower in different ways using different or stronger up gradable turret, our game will be following this but rather then you upgrading turrets you will be upgrading your self by evolving into a stronger species which means you can do better things and fight/move better and faster, as from the games i have played such as plants vs zombies and bloons i have seen that upgrading towers is a big part of the tower defense genre.