Build and upgrade towers to stop enemies marching across your map. Earn points by defeating all enemy waves so you can upgrade your towers.Part of the Tower Defense genre, Bolt Defense features clean graphics, easy to learn game play, 10 difficulty levels, 10 different maps and many tower upgrade options.There is also a FREE version of Bolt Defense. The FREE version has limited maps and tower upgrades, but is a great option if you want to try out the game before buying.