You must prevent the ball from escaping the dungeon. Three sides of the dungeon have walls; the bottom side is open — you can build a wall at the bottom by pressing the screen or clicking the mouse button. Note that this wall appears only for a moment, so time it carefully so you don't lose the ball. The ball bounces around the dungeon, and when it approaches the bottom you must block its path. Keep in mind, the game gets harder and harder — the longer the ball stays in the room, the faster it moves.