Swipe (or use arrow keys) to change the direction of gravity. For example, to make the balls move downward, swipe down. To make them fall upwards, swipe up. Gravity can be changed to any angle (unless playing with arrow keys, in which case you are constrained to horizontal, vertical, and diagonals if your keypad has them). A new ball is generated each time you swipe (or press an arrow key) Alternatively, you can use your device's accelerometer (if it has one) to change gravity by rotating your device. In-game gravity will point toward real gravity (note: may not work correctly in space, other planets, free-fall, etc…) New balls are generated as the device is turned more than a few degrees. Manipulate the direction of gravity to touch and merge balls of the same size / color / number together. For example, two '2' balls will make a '4' ball, two '4's make an '8' … As the number and size of balls increases, they will start to become tightly packed together. Once the pressure reaches a certain threshold (indicated on a pressure meter) the game is over.