This is the classical space invaders game, a very old but well realized
idea.
We control a sort of little cannon that can be moved toward left or right and
can shelter under some crumbling buildings.
From the top, slow but relentless, several alien monsters division advance.
Their only task is to destroy us and invade our planet. We must shoot them
all if we want to have a future.
Sometimes a little spaceship passes high that if shot gives us a bonus.
