The Earth is under assault from sneaky little bastard asteroids that you can't see until they've practically already terned Urbana, Illinois into a crater. Only you can save the planet from this threat, mostly because only you have big honking guns. One big honking gun to begin with, but an oddly chintzy human race pays you some money for each asteroid you keep from destroying millions of lives. Like maybe fifty bucks. At any rate, you can use this money to buy upgrades like more guns, cooler weapons, and automatic turrets. But the "turn up the contrast on your monitor" upgrade is always free.
Global Defense System [Heavy Games]
