the objective of each level in "crayon physics deluxe" is to guide a ball from a predetermined start point so that it touches all of the stars placed on the level. the ball and nearly all objects on the screen are affected by gravity. the player cannot control the ball directly, but rather must influence the ball's movement by drawing physical objects on the screen. depending on how the object is drawn, it becomes a rigid surface, a pivot point, a wheel or a rope, and the object can then interact with the ball by hitting it, providing a surface to roll on, dragging, carrying or launching the ball, etc. the player can also nudge the ball left or right by clicking on it, and in some levels, rockets appear and can be used as part of the solution.