Beat it!

The long-standing feud Between the humans and the Vorglon reaches its high point when the Vorglon turn it into a WAR of attrition.The Vorglon use mass drivers to send endless unguided cargo containers at high speed over the intergalactic shipping lanes. Humanity defends against these by deploying an Automatic Defense Base into the local shipping lanes, where it can destroy them effectively as they use the automatic Exit ramps, which are few in number.The Vorglon also send numerous other assailants which fly in under their own power at lower speed. You are charged with defending against them using your highly mobile Lead Defense Unit (which is constructed from lead to maximize weight so as to minimize recoil).To defend you must use your power shot and your weak shot. The Power shot is effective against all your opponents, but it is powered by human lives, so each shot you fire still reduces the human population. Make your shots count! Your alternative weapon, the weak shot, does not consume human lives and fires FASTER, but it does much less damange and is only effective against the weakest foes.