Balance the marbles on the plank by tilting left and right and roll them to match falling marbles of the same color. Make lines of 3 or more to score points and remove the marbles. Clear the marbles quickly or the weight will be too much for the plank and it will explode.
Plank features three levels of difficulty (from "Normal" to "Nnnnaaaarghh!") and various power-ups, including the "Shake" smart bomb that knocks out a whole line of marbles.
See the developer's demo video of the game in action: