Your mission in this great shooting game is to use your gravity launcher to destroy waves of enemy tanks and vehicles and survive for as long as possible. The launcher works just like a slingshot, use YOUR MOUSE to grab the energy ball and pull it back, then release to send the projectile flying. Note that enemy units receive more damage from collisions with each other than from your projectiles (unless your are using special ammo). You need to upgrade stability to be able to use new projectile types, otherwise they would be misfiring. Check in-game info/hints for more detailed information. Good luck!