Echo is a video game without video. It was made at the Malta Global Game Jam 2014 by Bernard Brincat and myself.
The game requires at least 2 people to play, and needs a mobile device and a laptop or tablet. One player plays as the bat; he or she is blindfolded and given a pair of headphones that are connected to a mobile device. The other player plays as the eyes; he or she is given a laptop or tablet that can send sounds to the other player, used to control his or her direction.
Below, you can see a video of a game in progress.
The source code can be downloaded from the Global Game Jam website here.