There are two requirements for an interesting audio game: physicality and a realistic sound environment.
Creating a sound environment is easy if the game is an audio analog of a real-world game. For example, in the casino games such as Blindfold Blackjack, Video Poker or Roulette, you hear the background of a Las Vegas casino. Actually, casinos are so common all over the world, I used a casino in Monaco for one of the games. For card games, I usually pick soft jazz or piano bar music – something relaxing, but interesting enough to keep you from getting bored; letting you concentrate on winning the game. A few times, I’ve picked the music based on the name of the game (Blindfold Dominoes uses a karaoke version of a song by Eric Clapton’s band Derek and the Dominoes).
Physicality means requiring a lot of body movements to play the game. For example, in Pong and Breakout, you can play several different ways. Both require you to move your phone to move the paddle. You can sit on a couch, and swing your arm from side to side to move your paddle. Or you can sit in a rotating chair, and move your body left and right to move the paddle. Or, you can stand up and turn your body left and right.
Any game that uses physicality requires calibration. When you first start the game, you swing your arm all the way to the left, then all the way to the right. The game learns how much you turn.
Most of the games that provide for arm movements also allow for finger control. Some gamers contacted me and mentioned their physical limitations, and wanted a way to play the game without large body movements. We added finger control for them. It’s also useful when you want to play a game, but you cannot move around as much.
Finally, any game that requires sound isolation – such as determining where a ball going to land – uses stereo sounds, and you must use earbuds or headphones to play the game effectively. And you need to put the left earbud in the left ear, and the right earbud in the right ear. I can’t tell the difference with my earbuds; I imagine that’s even more challenging for a blind gamer.
Every Blindfold game that uses stereo starts out by saying “You should hear this in only your left ear. If you hear this in your right ear, your earbuds are reversed.” But I suspect there are some gamers out there that play the games reversed, just because they can.