Essence Child is a great brainteaser from Living Energy Productions, a small group of amateur designers.
In addition to offering devious non-timed levels that recall the best of Chip's Challenge, the game comes with a nicely designed level editor and even a plot that unfolds as you play.
Like all great puzzle games, Essence Child is very easy to learn, but hard to complete. Your goal is to complete each isometric level by moving three balls of different colors (red, blue, and green) into their corresponding holes. Naturally, getting there is more difficult than it sounds: you need to deal with dozens of obstacles that range from simple (colored 'portals' that only allow balls of the same color to pass, and locked walls that require keys to open), to complicated (sliding paths).
Although most levels in the game are quire easy, all of them are well-designed and interesting enough for 10-15 minutes of your time per level. The graphics are crisp and attractive, the music and sound effects pleasing to hear, and the game even has different graphical 'themes' for different worlds that you will come across in your journey. Essence Child is one of the most polished freeware puzzlers I have ever come across, and although the relatively easy difficulty level may turn away expert gamers, puzzle fans who consider themselves beginners or are looking for a casual game will find much to like in this charming underdog. Recommended!