Game feel (sometimes referred to as "look feel" or "game juice") is the intangible, tactile sensation experienced when interacting with video games. The term was popularized by the book Game Feel: A Game Designer's Guide to Virtual Sensation written by Steve Swink. The term has no formal definition, but there are many defined ways to improve game feel. The different areas of a game that can be manipulated to improve game feel are: input, response, context, aesthetic, metaphor, and rules. Game feel is usually attributed to spatial games whose mechanics involve controlling the movement of objects or characters. Since the majority of games are spatial, studies involving game feel mainly focus on the movement and physical interactions between objects in games. The goal of good game feel is to immerse the player in an engaging and rewarding experience. A way to test game feel is to see if interacting with a game's most basic mechanics feels satisfying. At minimum, the game should feel engaging to play even after the plot, points, level design, music, and graphics are removed; if it is not, then the game may suffer from poor game feel. Input Input is the means by which a player can control the game. The physical input device used by the player has an effect on game feel; for instance, using a joystick to control movement feels natural because the joystick itself offers physical feedback. In other cases, like with touchscreens, the input device can offer little feedback and be cumbersome for the player to use. Game feel can be improved by using a control scheme that is easily understood by the player. Natural mappings allows a game designer to connect a game's movement mechanics to an input device. Realistic racing games, like Gran Turismo, make the most sense when using a racing wheel controller; in this case the input device directly matches the game's movement mechanics. Arcade cabinets often have unique controls to better relate to their movement mechanics. For example, Centipede uses a trackball as its main input; the inclusion of a trackball allows the player to move in all directions with ease, which is the main focus of the game's mechanics. Input sensitivity also plays a role in game feel. Sensitivity is defined as a "rough measure of the amount of expressiveness inherent in a particular input device." Each different controller has a unique inherent sensitivity, and