A group of stalkers, for the first time, reaches the very heart of the Zone-the Chernobyl Nuclear Power Plant-and triggers a cataclysm on the brink of a catastrophe. An immense blast of anomalous energy transforms the Zone: the once reliable and relatively safe roads are no longer so, the landscape is wiped clean by outbursts of anomalies, and previously unknown areas appear on the Zone map. Stalkers and expeditions perish or end up isolated within the lost territories.
This review may contain spoilers
While it is 'moar stalker' this prequel does not have the same impact as the progressive pseudo-RPG that is SOC. The game retains it's artistic sensibilities: the soviet aesthetics; the bleak landscapes, but the(new)later levels feel uninspired and many areas present in SOC have been inexplicably cut from CS.
The liberal use of scripted shoot-outs in CS and especially in Limansk are just wrong; over-used and literally unavoidable, making the later levels linear and boring.
The levels in SOC rarely used scripted fire-fights and were structured in a way that didn't necessitate them; and that was what endeared gamers to Stalker : a restricted sandbox game with emergent AI.
The emergent A.I has been altered and there is now a paucity of mutants and too many human opponents, with something being lost in the process so the world no longer feels oppressive. In SOC every faction (apart from the stalker's) had an intimidating disposition and was introduced to the player in an intimidating way: In the case of the Merc' faction and the Freedom faction there were cool scripted sequences; the army was dehumanised entirely, being introduced when butchering the Stalkers at Agroprom, while the bandits were also dehumanised as volatile animals.
In CS, with one of the development paradigms being 'join any faction', there is now an overabundance of friendly NPCs which detracts from the loneliness of SOC -- in fact there are now entire territories that are almost entirely safe. In SOC NPC's didn't need to befriend the player -- as they were hostile! -- they were characterised by the A.I! by their mystery/hostility.
The ending of CS(several of the aforementioned protracted action sequences) compared to the slow build-up of SOC(The intense path through Red Forest, to x19, through Pripyat, punctuated with blazing gun-battles followed by periods of tense infiltration in an intimidating environment) are not matched by CS.
If you are expecting more SOC -- this will disappoint.