What separates games from other forms of entertainment is that they provide interaction, however providing interaction it in the wrong way e.g. different from how the player would expect it or how the player requires it, means that people get frustrated playing your game --or worse-- cannot play your game at all.

More and more people are interested in playing games who do not fit the profile of the “20 year old male” that the game industry predominately seems to target. Playing a first person shooter on a console requires you to master two analog thumbsticks, four buttons and a number of triggers and or combinations of these. Not everyone is capable of doing this easily, such as the elderly, while those who have never played games before, such as people with disabilities, all face an increasingly complicated game interaction that withholds or restricts them from playing games in the first place.

Games are different from traditional software systems in the sense that most software systems are designed with the purpose to either completely automate a user’s task (such as ATM software) making the user obsolete, or to support a user in performing a task, such as a word processor helping someone write a letter. Games are different in that respect as they are solely developed for entertainment or educational purposes.

Interaction design affects two game qualities:

• Usability: if a player cannot figure out how to play the game, if the player has to wait, if it is difficult to learn to play the game or if game objects are awkward to use.
• Accessibility: if a player cannot understand what is said in cut scenes or cannot hear the footsteps of someone sneaking up behind him or her, because the player suffers from an auditory disability or if the game does not support the use of specific input devices such as one handed controllers or sip and puff joysticks that allow severely physical disabled players to play the game.

Usability and accessibility are two different but strongly related qualities. Accessibility problems can be considered to be usability problems for particular group of players e.g. those with disabilities. Unable to understand what is said in audio only cut scenes is an accessibility problem for someone unable to hear, but it is a usability problem for someone playing a handheld in a noisy environment without headphones.

This paper will argue that many usability-improving solutions in games can be beneficial for players with disabilities and the other way around. Game accessibility & usability should not be confused with gameplay. Gameplay focuses on providing interaction in such a way that it is fun. For example, moving a paddle to reflect the ball in Pong. Usability and accessibility however, deals with providing this interaction in such a way as the player would expect it, e.g. go up with the joystick to make the paddle go up rather than some exotic combination of joysticks movements.