The game, A Slower Speed of Light, is available as a free Mac and Windows download, and the source code to the physics engine is targeted to be open sourced in early 2013.

Here’s the game’s trailer:

The basic mechanic is simple enough: In a first-person environment, the player gathers various items scattered across the landscape. The more items that are collected, the lower the universe’s speed of light becomes, meaning color shifts and physical distortions start to appear.