Happy Dude(formerly known as the Black-White Game) is a color-changing puzzle platformer for PC/Mac/Linux. You play as a little box-shaped character named Happy Dude and your color determines how you interact with your environment.
When white, Happy Dude will collide with another white object, but he will pass in front of a black one. In a similar way, when black, Happy Dude will pass in front of a white object, but will be obstructed by a black one. Using this logic, the player must strategically invert Happy Dude's color from black to white (and vice versa) to solve challenging puzzles.