Alien Defense Instructions:

How To Play: Hold the mouse over the point where you want your missile to detonate. Then use the 'a', 's', or 'd' key to fire the missile from one of your launchers. At the end of each round, you get extra points for unused missiles. At higher levels you will receive more missiles, but the alien ships will advance more quickly and in greater numbers. The game ends when you lose all of your cities or all of your launchers.