Ardarium

Ardarium is a 2D simulation that automatically generates a random map and populates it with plants, animals, and humans. The point is to be something pretty and colorful that you can watch like a screensaver or play like a simple sandbox game.

Animals look for food, avoid danger, and reproduce. Humans do those things and also build nations, go to war with each other, and cultivate the land.

The world constantly changes. Land deforms because of erosion, tectonic uplift, volcanos and meteors. Elevation changes cause coastlines to shift and alter weather patterns. A forest might turn into a desert because it no longer gets rain. A submerged hill can become an island if the land rises above the water. A human settlement might thrive due to an abundance of food and then decline because of disease. Animals evolve to be bigger or smaller, faster or slower, based on which ones survive to reproduce.

Anything the player can do, like spawning animals or starting meteor showers, is something the simulation also does automatically. You can leave it running as long as you want and the world will continue as normal.