The goal of the game is to color the whole board in one color.
You start with the block in the upper left corner and the blocks that has the same color and are connected to the first. You advance by clicking on a different block with a different color.
All the block you control will change to that color. You will also gain control of all the blocks that are adjacent to blocks the blocks you control. (And the blocks adjacent to that and so on.) Continue until you control the entire board.
You can change the boardsize and the number of colors either on the right of or under the board depending on your screen size.