Your mission in this collision-physics based defense game is to destroy the advancing enemy forces using the Gravity Launcher Installation. Bounce your weapons off walls, throw tanks into each other, and create catastrophic collisions. You have a certain amount of lives that represent how many enemy units you may allow to pass behind. The gravity launcher works like slingshot, use YOUR MOUSE to drag the ball and release to set it flying. The farther you drag, the faster will it fly, however you must watch the stability indicator. During the game you will gain skillpoints to upgrade the gravity launcher, obtain new abilities and projectile types. Try avoiding any explosions near the launcher as it can be easily damaged. Sometimes when you destroy enemy unit powerups will fall out, click them to pick them up. Good luck!