This is the story of a convict.  One night, while he and his cellmate is about to sleep, he began telling stories about how he ended in the cell.  Apparently, it was a dark night when it all began.  He remember that suddenly there were aliens all around him and he has to defend the world against the invading alien.   The game is played with a mouse and a keyboard. You need to kill all the alien that are out to get you.  Collect anything that they drop.  Upgrade or buy new weapons when you have enough money.  To pick up the weapon and health pack, you need to press the “space bar”.