Blocky is played on a randomly-generated game board made of squares of four different colours. We call the game board a "block." A block is either:
- a square of one colour, or
- a square that is subdivided into 4 equal-sized blocks.
Each player is randomly assigned their own goal to work towards: either to create the largest connected "blob" of a given colour or to put as much of a given colour on the outer perimeter as possible.
There are three kinds of player moves:
- rotating a block (clockwise or counterclockwise),
- swapping the two halves of a block (horizontally or vertically), and
- "smashing" a block (giving it four brand-new, randomly generated, sub-blocks).
What makes moves interesting is that they can be applied to any block at any level. For example, on the board on the left below, the user has chosen a block (highlighted) that is two levels below the top level. Rotating it clockwise would result in the board on the right.