Defendo Free Space 3.1

You are the commander of the defense alliance of star systems. Your task is to defend the planet from destruction by an armada of invaders! Install tools for the defense of the planets. For every destroyed ship you will be awarded the money to spend for the installation of new tools and improvements already installed weapons. You need to keep at least one-planet. To win a level you need to survive the allotted time and you have time to dial the number of points needed to win.