Age of Empires III is the first true follow-up to Age of Empires II, after developers Ensemble Studios had taken a fairly lengthy vacation from the series to work on the Age of Mythology spin-off and its expansion. While AOE III stays true to its roots in some respects and has changed significantly in others, it still represents an RTS done well, and is helped by some stunning presentation and lasting value.
AOE III moves the series forward a few hundred years to a colonial setting. The major European nations are battling it out over the New World, with the conflict taking place over five ages, culminating in the industrial age and all that goes with it (the first locomotives, mass production etc). While each age offers improvements, the step from one to the next isn't as drastic or as notable as in previous games. Right from the start you have gun powder and even your settlers can use guns to hunt. Still, moving through the ages is a vital part to the game.
Eight European civilizations all want a piece of the New World, with the British, the French, the Spanish, the Dutch, the Russians, the Portuguese, the Germans, and the Ottomans all involved in the conflict. A few others will make short appearances and Native Americans can be allied with and used to bolster armies. Each civilisation has its differences in terms of economy and military. For example, the British gain new workers when a house is built, the Russians can train light infantry quickly and the Ottomans have some of the biggest guns in the game. In truth, the differences aren't huge, but they are enough to be noticeable as you play through the campaign.
The single-player campaign is lengthy and set over three acts; each is a generation apart and connected to the last. Before you start you can take part in a very useful tutorial that will guide you through the basics of the game, teaching you how to set up colonies and gain resources. Early levels are pretty simple with your opposition not putting up much of a fight, but as you progress your enemy will increase in size, often taking up a number of locations on the map, making your task considerably more difficult.
'Resource gathering has been simplified a lot in AOE III...'
Your goal is usually to wipe out the opposition, and this means everyone, not just all the buildings or the army - every last soul. You do have to go on search missions now and again, to look for treasures or important objects, but most objectives are to kill your opponents and to set up colonies. Managing your colony is very simple. After building a town centre your workers can build various other buildings, such as houses and barracks. You can only create men if you have enough houses to support them, so it's important to build up quite a large area of living quarters. You don't want to be left needing to make more soldiers, but can't because you're waiting for more houses to be built.
Early on while you're waiting for your workers to set up a basic settlement you can use your Explorer to uncover new land and set up trading posts with Native Americans. Your Explorer can't be killed, but if attacked he will fall to the ground injured. He'll only recover when friendly troops pass near him and on occasion will need to be ransomed back from the enemy. He can also be used to collect treasure and earn you experience points early on in the game.