Alien Invaders

London is in peril! An Interplanetary Battle Fleet from Mars - whose inhabitants are infuriated by our claims that their planet is dead - has attacked. The Ministry of Defense is asleep, so you have to defend the city with just one missile launcher. You can move the launcher to the left using capital Z and to the right using X. Press F when you are ready to fire. The Aliens descend cautiously at first, but be on your guard. If you let a single ship through, London will be devastated.During the game you score points for each invaders you hit - more points for a ship high in the sky than for one close to the ground.