Something I KNOW people will post in, because 2 of our most well known members and me play this.
The both series (Dynasty Warriors and Samurai Warriors) follows the events of Feudal Japan; or the novel Romance of the Three Kingdoms). You take control of a notable figure from that time period and along with other allies, fight through hordes of enemies and officers until victory requirements are met.
Victory usually consists of taking out the enemy general, but sometimes, your general may have to escape, take out all enemy strongholds, or defeat all enemy officers. The maps are large and colorful, and you can call upon a horse at anytime to help you get around faster.
There are also certain objectives you have to complete along the way, such as taking out a specific officer or escorting some troops. Failure to complete these yields consequences as more enemy troops will often appear, or the map will even be set on fire.
How would I describe the controls? Well it's like Monster Hunter, God of War, and Ninja Gaiden all had a threesome.
The game is fun, but the controls take getting used to. If you plan on getting it, rent it before putting a lot of money into it.