A set of scenarios that can go by in an hour or two and only one other game type mar an otherwise great sim game.
Sim Earth is the very definition of simulation. It throws you on to a random planet much like Earth 4 billion years ago. You must then mold it into a life sustaining planet by altering things like plate tectonics, axial tilt, volcanoes, cloud albedo, and rainfall. You can also more directly change the planet by altering it's atmospheric makeup; through volcanoes or other natural means, or by placing buildings that generate different gases. For example, if I place a water vaporator it will gradually add water vapor to the atmosphere, and if the rainfall level is increased it will turn into oceans. When your planet begins to evolve life, you can even change things like rate of reproduction, or how rapidly life advances. By increasing the reproduction rate, your planet will become overpopulated, but if it is too low, species will go extinct. You can also add different biomes, such as boreal forests and jungle, or deserts to your planet to add another layer of complexity. Eventually, the planet will evolve a sentient species, which will conduct wars and even the occasional nuclear war until it advances to a high enough technology level and migrates to another planet, where the cycle repeats. There are also specific scenarios, some of which require you to terraform planets such as Mars and Venus, and even save the world from being taken over by robots (think Matrix). Some of these have time limits. Unfortunately, these scenarios go by very quickly. Some of them you can even finish in a few minutes. Another bad thing about this game is that to develop a planet takes time, so you might as well pull out a book while you are waiting for things to happen.
Now lets get to the technical parts of the game. The graphics arent very impressive, even for being 20 years old. On the other hand, the game has a nice soundtrack that fits perfectly with the grand, planet spanning gameplay.
The last thing i'm going to mention is that this game is NOT for everyone. Some scientific knowledge and thinking is required to deal with the controls.
You have to really use your head to figure out how Thermal Transfer is going to
affect your planet. Another downside to this game is the steep learning curve. Your basically thrown into the game with no tutorial and all these non-descript buttons to press. If you can master them however, controlling your planet is a breeze.
Overall, SimEarth is a great simulation game for anyone who has an interest in the subject.