Nihilumbra is described as 'Use the power of the colors to change the world around you, and join Born on his adventure while he tries to stay alive and escape from his inevitable fate: being consumed by the pure emptiness. The Void'. There are three games similar to Nihilumbra for a variety of platforms, including Linux, Mac, Windows, Android and Android Tablet. The best alternative is Limbo. It's not free, so if you're looking for a free alternative, you could try Minilens.
Welcome to the Minilens experiment. A thousand years into post-apocalyptic Earth, many forms of life have gone extinct, including humans. An alien robot series, called Minilens, is cleaning up the Earth and collecting the surviving flora for research purposes.