Yesterday the skies were peaceful. The birds were kings of the skies, flying around carefree and twittering away joyfully. Below them the rest of the world went on with its business with no idea about what was to come.

Then They came - not just one but a whole horde of UFOs. At first their arrival was greeted with excitement and wonder. What would our first neighbors from space be like and what marvels would they bring to planet Earth. The elation did not last for long though - it soon ended when they started to blast the cities of mankind into smithereens.

As commander of one of Earth's last remaining defences, the planet's future survival depends on you. If you can keep this base from being destroyed, humanity has a chance of regrouping here and the possibility of redrawing plans of action to save the world.

Your super high-tech missiles will fire wherever your mouse is pointing when you click your left mouse button. Those aliens are smart though, and they'll use cloud cover in which to hide. The power you need to fire the missiles is running out quickly, leaving you with only one minute to shoot as many UFOs out of the sky as you can. The higher your score (shown at the left of the bar on the game), the less likely the planet will be overrun by the invaders.

How high can you score to help the world survive?