We're getting quite close to the launch of Dynasty Warriors 9 now, so you can expect to see at least several more videos like this one over the next few weeks. The gameplay's in Japanese, but it still gives us a decent idea of how the title's open world missions work. Basically, you're able to pick and choose between a bunch of different battles, each of them with their own objectives and challenges. The missions that you end up clearing will impact future clashes, too.
Watching the gameplay, it seems pretty cool. It's like you're actually a general going from battle to battle in a field of war.