We wanted a solid example of design that seamlessly blends commercial and accessibility issues, and spoke with Mike Ambinder of Valve Software.

Valve is highly-regarded in the disabled gaming community, particularly for their work with adaptive control devices.

"Most of the accommodations we make for disabled gamers (closed captioning/subtitles, colorblind mode, in-game pausing in single player, easier difficulty levels, re-mappable keys/buttons, open-microphones, mouse sensitivity settings, use of both mouse and keyboard and gamepads, etc.) stem from functionality added to improve the experience of both able and disabled gamers," Ambinder told us.

"For example, both groups of gamers benefit from the ability to pause Left 4 Dead 2 if they need to take a break or escape from the action, and the addition of subtitles allows all gamers to process the in-game dialogue/sound effects through an alternative visual medium if that is their preference.

"We may design for an optimum experience, but any accommodations we make to extend the accessibility of our games should benefit folks (both able and disabled) who choose to consume our content in an alternative fashion," Ambinder said. "For example, in the initial implementation of Left 4 Dead, there were no glows around the survivors indicating their location in-game. In our first experiments, we thought that verbal cues transmitted from other players would be enough to enable cooperation and to guide players to teammates in need.

"We soon found out that more information was required, as relative locations could not be adequately described in sufficient detail nor with sufficient speed to enable a cohesive experience. To remedy this, we added in the glows (visible through walls) which silhouette each teammate and provide a salient, visual cue to in-game location -- improving the communication between teammates for all gamers (and especially for gamers who have difficulty hearing or speaking)."

As the Wii and Kinect demonstrate, increasing usability through accessibility can open up exciting new avenues of gaming that permanently change the playing field. "We're always curious about alternative control devices and are constantly researching and playing around with nontraditional controllers in the hopes of finding an approach that might lead to an interesting gameplay experience," Ambinder said.

"In particular, we're intrigued by the potential of eyetrackers and the eventual ability to let gamers use their eyes as active controller inputs. For example, it may be possible in the future to let the eyes act as a proxy for the mouse cursor, letting gamers transmit navigation and targeting inputs via eye movements. If you couple this approach with the use of blinks or other proxies for button presses, you may remove the need for a mouse and keyboard (or gamepad) all together."

Eliminating the narrative of divisiveness around "accessible design" and rather focusing on usability will turn these sorts of considerations from an added cost into a value add. It's the innovation behind improved usability that winds up serving us all, and the more we can encourage game developers to tackle the challenge, the more varied, deeper, and ultimately enriching our gaming experiences will become.

(FarmVille image taken from Lynspirations)