For those with paralyzed or missing hands, sound could be a great alternative form of input. In a top-down shooter, for example, one could blow (such that it makes sound) to make the character move toward the top of the screen and suck to make the character move to the bottom of the screen. To shoot the player could make a gun sound like “pew pew.”
I started by creating a simple top-down shooter. Then I experimented with the minim sound library so I could use the microphone as input and viewed the waveform. To determine when to fire, I calculate the sum of the absolute value of the slope of the waveform generated by the microphone so when the wave is reall noisy, the gun fires.
I didn’t get my original idea to move the ship via blowing and sucking to work but the ship fires when you make gun sounds and rapid fires when you make the “shhhh” sound. I think, even for someone who isn’t paralyzed, this form of input could be really fun.