Fun, but far too easy.
The gameplay of DW4 is fairly primitive, as the game is so easy, that it's ridiculous. You can kill hundreds of enemy soldiers in a few minutes if your good enough. Enemy AI are so stupid that they dont even retaliate, unless they are highly ranked soldiers. The campaign is fairly interesting, as you they have cutscenes after each chapter, giving you a story to follow. Unlocking all of the officers can be a fun challenge, as there are over fifty of them. But in the end, you will get bored after an hour or two, and feel guilty for having wasted two hours of your life which you'll never get back.
The graphics are quite good, particularly in the cutscenes, where many of the characters look quite real. Though when you attack someone, you can often send them flying meters with just a standard sword swipe.
The sound's great, with a really cool eletric guitar soundtrack and chinese instruments. The sounds of dying soldiers, and the voice acting for officers is also quite well done.
In the end, the game has little purpose, as it can pretty much go for ever. You can kill thousands of soldiers in two hours, and realise that it was a waste of time. Not only this, but the game barely changed anything since DW3. But the game is fun for what it is, a "cheap frills" game, and it should be commended for that.
I reccomend you not buy this game, but rent it first. If you reckon it's fun, buy it cheap.