We like Pulse, an independent project and IGF finalist from Team Pixel Pi, for a couple of reasons. One, the main character is blind, and the only way to reveal the world around him is through sound. Two, the primary way to create these sounds is to throw adorable critters called Mokos around the environment.
As has been proven before, there are few things more satisfying than flinging adorable critters against solid objects. Doing so "illuminates" the world, so to speak, giving the player an idea of their surroundings. It's pretty neat, but you don't have to take our word for it, as a free prototype is available now for both Windows and Mac. We should also mention that, occasionally, you feed Mokos to slavering monsters (only out of necessity, of course).
Team PixelPi is currently seeking funding for Pulse on Kickstarter, with the ultimate goal of $75,000. The game will be on display at the IGF Pavillion at GDC, and you can bet we'll be checking it out.