Alien Destroyer

A Space Invaders variant. Your laser base must destroy aliens dropping bombs as they advance down the screen from left to right. The laser can hide behind one of three shields, and a spaceship occasionally flies over, which scores 100 or 200 points. The game is over when the invaders land (i.e. reach the bottom of the screen) or when all of your three laser bases are blown up. A bonus base is awarded after the second wave of invaders has been eliminated.