The tested formula has been tightened and polished, giving the most stable and atmospheric experience of the series yet.
All in all, Call of Pripyat is more of the fundamental same, with more tweaks and features added in – like the natural progression of the curve that Clear Sky started. Some features have been removed, like the faction wars, but other aspects have been vastly improved. It's the little things, like the more accessible hotkeys for medkits and most importantly, bread, and the inclusion of a clock on the HUD which helps to inform you how much of the pitch black expanse you must endure before it brightens up somewhere around 4am. You can sleep. You need to eat more often than the older games. You need to find cover for emissions quite often. All adding to the immersion factor.
A feature that I find particularly effective is the repair/upgrade system. A problem I encountered with the previous games was that I had the bank balance of an oil tycoon, and needed it since the game tried to balance by making all the high-level items horrendously expensive. Now, things seem to be more appropriately priced, and you can invest your money in repairing your items (which is far more important since loot needs to be fixed, usually, before it can be sold) and upgrading them – meaning that you can sport your own customised weapon. This was in Clear Sky, granted, but wasn't executed anywhere near as effectively, I think.
I also prefer the narrative viewpoint of the story this time around. Shadow of Chernobyl had a good thing going with "Marked One"/Strelok, but the characterisation in Clear Sky ("Mercenary Scar") was very poor. The idea of a military agent going in undercover is appealing, and starts you into the game with some actual objectives, with more importance than "kill this dog" and "retrieve this coat". Plus, you can actually walk around the world now without getting shot at by every twitchy-fingered Ukranian – you can approach Bandits, and even some Monolith, and whilst they aren't inviting you in for a round of Scrabble, it's nice to see the AI making intelligent judgements based on the situation.
The graphics have improved also. The game uses the same core engine as its predecessors, but with more and more goodies packed in. The environmental sound, as always, is top notch and incredibly immersive, using surround sound and hidden surprises diligently. The voice acting however, is, errrr, again quite humourous, but not quite as bad as the previous games.
All in all, if you want to experience the STALKER series for the first time, I'd perhaps buy the first one, and then this – or just this, it does a good job of delivering the Zone to you without being that connected to the others. If you already own the first two games (like me), I'd still give it a try if you really enjoyed the first two. I wouldn't rush out and buy it, but if you see it on offer, or just fancy a new STALKER experience, I'd definitely recommend it – since this is the most solid and approachable game of the series yet. It seems as though GSC have listened to and observed the modding community and implemented features introduced in mods for the first game years ago.
Though, it leaves you asking the question, "What next?". This formula has been explored enough now, I reckon, and the series is ready for a new overhauled sequel. Take your time, GSC.