The object is to get more points than opponent. Choose from the numbered balls in the active play line. Score points by selecting positive numbers, and lose points when selecting negative numbers. Two players choose the ball alternately, the game ends when there are no more possible moves. The player with the most points wins.
The player who moves first has a little advantage, in order to compensate this, we use "swap rule" when play online: After the first move of first player, the second player is allowed to swap the sides. In order to apply the swap rule, just tap the "Swap" button under the "More.." menu.
In online play mode you can play with others over internet. After login you can join game tables created by others or create your own one. Password are required to join private tables. ELO rating system is used to calculate the relative skill levels of players, initially everyone have 1500 ELO. If you play with someone of lower ELO, you get less points if you win, but if you lost you lost more points, if the game reach a draw, you still lose points. But if you play with someone of higher ELO, the situation will be in contrast, you may get points even the game reach a draw. You'd better play with someone of ELO near yours.