Stackpack is the ultimate puzzle strategy game. It can be played with up to 4 players on a single iPad. The goal of the game is to conquer the map by overtaking all the other players.

You choose the number of players before you start by checking the grey box for each player (at least 2). Then you choose a 'singleplayer' game (the human player starts, the other players are computer players) or you start a 'multiplayer' game (the human players take turns to place a ball on the map).

Players can place a ball on a blank square or on a square already occupied by your own balls.

Each square shows a number, this number represents it's critical mass (two for corners, three for edges, four elsewhere).

When the number of balls on a square reach the critical mass, the ball explodes and scatter in all directions. If any of these scattering balls land on an opponent's ball, they are captured and become yours. If this scattering causes other squares to exceed their critical mass, then they explode as well, and so on, until either the explosions stop or there are only one player's balls left on the map. That player is the winner!