As the title suggests, Crayon Physics is a puzzle game of crayons and physics. The goal for each of the seven levels is to move a red ball so it hits the stars. The mouse is used to draw physical objects of different colours which can move the ball, block it or provide a bridge. The objects interact with each other as well as with the environment. The left mouse button is used to draw, and the right one to erase objects. When the ball falls off the screen, it reappears at its original relocation. It is also possible to reset an entire level. The game is played against a scrap paper background and all objects have a crayon art style.