Empire Earth looks and sounds a lot like Microsoft's Age of Empires. In fact, Rick Goodman, the lead designer, was also the lead designer of Age of Empires. At first glance, not much is different: Empire Earth is a real-time strategy charting the passage of civilizations through time. There's single-player and multiplayer support, hundreds of units, and stunning graphics.
But then a few new things pop up. The graphic engine is fully 3D and requires a 3D video card, where the Age of Empires series is 2D. Combat is more detailed, encompassing battles on land, sea, and air but at variable scales. Empire Earth supports zooming the view close enough to focus on small numbers of units. In a demo of a sea battle, we saw ships meticulously detailed, with moving turrets and damage smoke.
You can create your own civilization by assembling it from a variety of characteristics. Perhaps the most interesting element about Empire Earth is the grand time scale. From the Stone Age to the future, Empire Earth looks like Age of Empires, Settlers, SimCity, and Command & Conquer, all wrapped in one box.