Boulders in five different colours are dropped from the top of the screen. Somewhere above halfway the playing field there is a wall which will stop boulders from falling any further. There are two holes in the wall through which the boulders will continue their way down.

You control the game in 2 ways:
* With the stick left & right you control the wall, moving the holes left and right. Any boulder which is inside one of the holes will also be moved.
* With the left & right shoulder buttons you move all boulders above the wall left or right (including the ones that didn’t even drop on top of the wall).

Points are scored only below the wall. If any 4 boulders in the same colour form a horizontal or vertical line or a block (2×2) they are removed and points are scored. A line scores more points than a block. Even falling blocks can be a part of a line or a block. Higher levels give more points.

A higher level means the boulders are falling faster and new boulders are also dropped faster.

The game is over if the playing field above or below the wall is – at any point – filled up to the top. It can also be stopped by pressing Start and Select simultaniously.,0,0,0,25,2620