Age od Empires III is a must-have game for those are interested in RTS game.
Firstly, the campaign mode is long and very enjoyable though it's based on fictional stories about Black family. There are three "Acts" and each act has about seven or eight battles which are different form each other and have a variety of objectives. However, the campaign mod is rather easy and it might take you about three hours to complete one act.
The gameplay has some new features and contents. Now you can get reinforcement and shipments by home cities. You can also train 5 units in each queue ( funnily, you can only train one settler in each one ). There are eight civilizations and each one has unique units and cards. As for the economy, you can gather much food and gold easily and very fast whereas wood still runs out quickly. Someone may consider those new contents are just minor changes but to me, they make the game more enjoyable. Firstly, unique armies and home cities diverse the strategies. Secondly, you don't have to spend too much time on economy, so you can concentrate on fighting. As for the bad, I find cannons are too strong and outports are weaker than those in Age of Empires II. Finally, it's illogical when an archer has a wider attack range than a musketeer.
In my opinion, the best thing of Age of Empires III is the graphic. Well, it's colorful, beautiful and very true. When a cannon fires into a building, it turns into pieces and collapse! The water is very dramatic. The game sounds are great too though they are not different from those of its predecessor.
Age of Empires III is a worth playing game. The gameplay may not be an innovation, but the graphic would enhance you.
I'm not an English so I'm sorry for any mistakes.