Universal Sniper

In Universal Sniper, you start at the laboratory where everything seems to be running just fine. An air gun has been installed called "Heaven's Punishment". Aliens suddenly come in and kill the scientist and take over this weapon of mass destruction. Will the aliens destroy us for good? You shall play Eric, who will go through a series of missions to complete. You get a certain number of rounds to use for each mission and a code so you can come back to it later. The missions will grow in difficulty and increase in fun. You'll find it hard to stop playing once you become successful in your missions. Can you save the world in Universal Sniper?