Norwegian developers Sarepta Studio are working on a rather interesting platform/puzzle concept called Shadow Puppeteer. Set up as a co-operative game one player controls the shadow, while the other controls the boy taking turns solving puzzles to progress through the levels. It may sound like a simple idea, but the use of various light sources makes this game a bit more complex than what you first may have thought. Have a look at this interview with lead level designer Klas Lothe, where he explains the concept and what platforms they're hoping to release it on later this year.