Cel-shading is a graphical style that makes 3D games appear flat like cartoons. It is used in games like Zelda, Ben 10, and Futurama. Abstract styles emphasize lines and colors without resembling reality, as seen in Donkey Kong and Tetris. Photorealism uses cameras and photos to create realistic paintings and games like FIFA 13 and GTA 5. Exaggeration amplifies aspects of games like large weapons in Dragon Ball Z and characters' features in Alice in Wonderland. The document discusses these four styles and provides examples of genres and target audiences for each one.