Parallax

Parallax is an option in the editor that allows graphics to move more or less relative to the camera's position. This can be used to create the illusion of depth on a 2D plane.

Parallax can only be used on graphics or groups that consist entirely of graphics. The strength of the effect can be controlled by up to 2 decimal points, from -3 to 3.

Use as a 3D effect
Using multiple layers with varying parallax levels, it is possible to create rudimentary 3D shapes in the level that can be collided with. The trick was first discovered by CodySmith and has been used in some of his levels, such as Jolly Pachinko and Jolly Football.