Interesting...
The orginal game S.T.A.L.K.E.R:Shadow of Chernobyl, was voted the most atmospheric game of the year and Clear Sky doesnt stray from that title. The game keeps the theme running in this game with dilapidated structures, campfire gatherings and varied mutants.
The changes in this game involve a lot of graphical improvements and animation alterations. Characters look a lot better then in the previous game and facial animation looks sharper as well. Even as I run the game on a Pentium 4, it still looks good.
The gameplay of the game remains close to the previous game. However, You get to access different areas that were not available in the first game and many things have been added. The main addition is the faction wars. The game can be played in a variety of ways and any faction can be joined to conquer the Zone. You are given objectives to take over control points, destroy targets and defend positions to ensure the faction you have chosen to help becomes more powerful. Trading has been expanded as "Technicians" are available to help upgrade/repair weapons and armour.This helps from downloading mods like many did to repair items in the previous game. Also, guides are available and can take you to ares in the Zone in a Quick Travel method. For a price, of course.
There is a lot more to do in Clear Sky, with different ways to play the game and multiple endings. Enemy AI and friendly AI has been upgraded as the AI know how to use cover effectivley and fire from cover without running from cover.
The difficulty of the game is harder than the previous S.T.A.L.K.E.R. Enemies know how to flank corectly and the weapon physics are quite realistic. One shotgun blast from a close range can mean the death of you. Using weapons is different from your average shooter as head shots are harder and your guns can jam. Due to the weapon physics, guns act a lot more realistic.
The story of the game is set before the previous game ( "the official prequel" as said on the box.) and you play as the Mercenary Scar who is requested to kill Strelok, prior to the events of S.T.A.L.K.E.R: Shadow of Chernobyl.
All in all, by only playing a couple of hours of this game, I can say that is is a very good game. It adds upon an allready magnificent game and adds more depth. Only time will tell to see how this story resolves ^^.