This is the underappreciated game of 2005-06. It is fascinating and addictive and not as simple as it appears.
You begin the game with the an introduction to a digital world created by a programmer to study artificial intelligence. He created the Darwinians, simple, green men reminiscent of 1980's era video games. He also created in them free will. Then we learn that their world has been invaded by viruses, and it becomes your task to restore Darwinia to its former glory by eradicating the virus and restoring the entire ecosystem.
You start out the game with only one or two types of units, which are called "programs." In the beginning you can only run three programs at once on your task manager. This is an interesting take on an RTS because you don't use resources, except for your ability to manage a limited number of programs at once.
One particularly entertaining unit is the squad, which you can ask the programmer to work on upgrading as the game progresses, which simply takes time. The squad is a line of 3 to 6 soldiers that you direct around the field with clicks of the mouse. You can fire their guns in unison at a virus by right clicking on an area of the map and they will immediately start spraying that area if it is within range. While firing you can click the other button, which will lob in a grenade, fire rockets, or call in an "air-strike" depending upon what you are doing. The reason why this is so entertaining, is that in RTS you never get that visceral arcade game feeling from just watching the little units fight, in Darwinia you actually make them shoot, and you lob every grenade with every click. I loved hurling rockets into nests of virii and listening to them scream and explode into little digital chunks.
There are also engineers, who take over buildings, such as incubators. There are armored units that carry darwinians whom you can arm with lasers and grenades. The armored units transform into gun emplacements at the destination and are manned by Darwinians, and can be taken over by evil red Darwinians who are infected with the virus. That are other units as well.
The imagination that went into the game is impressive, because as you take back the "land" from the evil red virus, you activate the ecosystem. There is an entire cycle of life in Darwinia. For instance, when you kill virii, which are made of out corrupted Darwinian souls, you use engineers, to deposit them into an incubator, and watch as the building processes the red souls, into new Darwinians that can then be used to operate systems, buildings, or fight! You can also recycle dead good green Darwinians souls in the same way. If you don't gather the souls in time, they sort of float up into the ether.
Later, you learn that everything floating into the ether gets recycled as well, because the souls precipitate back down to the digital ground and settle on collectors that you need to get up and running again. The programmer comments to you about the history of his world at key times as the story unfolds. I won't spoil the whole thing for you, but the point is, more thought went into the world of Darwinia than went into 90 percent of the games on the market.
On a design note, I was very pleased to find that this game runs every screen resolution you can think of, including widescreen resolutions, and the animation, and camera movement are very, very smooth. I really appreciated an innovative take on camera movement, which is the most intuitive I have ever seen in a game.
I hope more people play this game, because it really captures what gaming is all about... fun.