Undermine

Undermine is a 1-player arcade game for the VIC-20.

The player controls a bat within a small cavern. To the north are the wide plains of Xylon, to the south lies the open sea, protected by a storm wall. A ball bounces about inside the cavern, and the player tries to direct the ball to break away the wall to the north while trying not to hit the wall to the south. The player determines game speed and the thickness of the sea wall, and if the storm wall breaks, the cavern floods and it's game over.