I preferred this game to the original. A truly exhilarating third person stealth/action experience!
One of the main reasons that I prefer this game to the original is the fact that the checkpoints are much more frequent. This game is mostly trial and error in both action and stealth sequences so the fact that you aren't pushed way back after failing a mission was a relief and spared me a lot of frustration. Another reason I like the sequel more than the original is the implementation of new features. There are more guns this time around as well as the return of a few old favorites and for the most part the action hasn't been trifled with so those who have played the original won't have to learn a new set of controls. The enemies are much smarter now and can shoot you in the head. This makes finding cover a thrilling and important task. I also thought the frequent cut scenes and story were a fantastic continuation of the original story. It is also much easier to know what to do and where to go instead of getting lost in monotonous environments trying to find sneakily hidden points to climb up or down like in the original. Finally this game is more violent than the first as occasionally a foe will die and produce a pool of blood under him.
In this game you are in a race against time, as your partner Lian Xing has the Syphon Filter virus in her bloodstream you must find data disks in order to bargain with the mysterious agency and save her life. There are also some neat missions in which you play Lian Xing herself.
In conclusion this is a great third person action game that improves on the original and doesn't pull any punches with the violence factor. I would highly recommend it to fans of the original and newcomers alike.