From online manual:
To say that Enigma is a puzzle game is an understatement. Enigma is really a huge collection of puzzle games, and each of its 550 unique levels challenges the intelligence, dexterity and sheer willpower of its players anew. Enigma is simple to learn, challenging to play and hard to master. It can be enjoyed by players of almost any age. It contains hundreds of levels. And if that weren't enough, it's also completely free. If you like puzzle games and have a steady hand, Enigma will probably keep you busy for hours on end.
The object of the game is to find and uncover pairs of identically colored `Oxyd' stones. Simple? Yes. Easy? Certainly not! Hidden traps, vast mazes, laser beams, and, most of all, countless hairy puzzles usually block your direct way to the Oxyd stones. Enigma's game objects (and there are hundreds of them, lest you get bored) interact in many unexpected ways, and since many of them follow the laws of physics (Enigma's special laws of physics, that is), controlling them with the mouse isn't always trivial ....
The original goal of the Enigma project was to keep the spirit of the Oxyd game series alive, after its publisher decided in 2002 to leave the gaming business. Fans of this famous game will have their déjà-vu. But over the years, Enigma has absorbed ideas from countless other popular games, and added its own unique twists to each of them.