Heli Intrusion, a cool physics shooting game using box2d engine

Survive waves of invading hostile helicopters! Shoot them with your cannon and try to make them rotate til they explode. Let them knock into each other to create massive chain reactions of explosions! Earn money with each exploding helicopter to repair and upgrade your cannon. Shoot the ragdoll style soldiers to earn more money. Don't let the helicopters escape or you loose live.
Target with your mouse. Click or click and hold left mouse button to shoot.