I thought it was really nice that they put the ultimate fate of the main character of this first series of Stalker games in the player's hands again. He wasn't merely an NPC, you had an actual reason to want to see him get to the helicopter.
Did you realize Clear Sky's secret, by the way?

Run by scientists who worked at the X-series of labs and may have been involved in the noosphere experiments that formed the foundation of the project to create the C-Consciousness? Or that Clear Sky members were incorporated into the Monolith Faction after the events of the game?

I also think that the experiments that in the long run led to the creation of the C-Consciousness predate the X-labs (which were a continuation of and expansion on earlier work) and even the original Chernobyl incident. I think that the timeline actually starts with Limansk, based on what we learn about the place in CS.

I disagree, partially. The X8 documents are quite clear that noosphere research occured in the X-labs. While Limansk may have been the site of the earliest noosphere research, all evidence indicates that this research was also continued in X16, X8, and X7, quite possibly X18, and the CNPP. (Assuming X7 isn't the CNPP) Consider that a model of the Duga-3 antenna array can be found inside X8. (Note, Duga-3 is the Brain scorcher)

We still haven't found out whether or not Duga-1 and Duga-2 were part of the same research that went into making the Brain scorcher. It'd be interesting to see what could happen if Duga-1 and Duga-2 were in fact capable of interfacing with the noosphere. Considering that they are in southern Ukraine and not inside the zone like Duga-3 is.

I think the documents are quite clear that the discovery and subsequent experiments concerning the alteration of the noosphere followed from experiments into psy-effects over long distances (the blue file). The Duga-3 antenna is actually located at Limansk in Stalker, although a lot of people misinterpret the completely fictional rainbow emitter in Red Forest as Duga-3, probably because the real antenna is located in a forest. Forrester's dialogue heavily hints at Limansk being the site of psy-experiments, and interestingly enough notes it was never evacuated. I suspect the implication is that X-labs were built to continue the research started at Limansk.

I don't disagree that Limansk may have been the site of the earliest research, but what I'm saying is that there is evidence that at the very least X8 coexisted with Limansk.

The intro to CoP establishes that the X-labs were established after the incident at Chernobyl. Limansk obviously was not
I really don't think Limansk is a giant red herring. If we assume that, it's heavily implied these experiments are not independant of each other but that one led to the other.

However, Limansk was also not evacuated after the Chernobyl disaster. Limansk could have remained a functioning site when the X-labs were built, and doesn't X8 have a clearly labeled scale model of Duga-3?

how many trips to the center of the Zone Strelok made, in what order they were and what happened during each one.

I like the idea that C-Con vastly overestimated their influence on the Zone and underestimated how much the Zone influenced them, but the only thing we have to go on is Strelok saying the creators were not in control anymore. Is someone else in control? Is the Zone running wild? Maybe the Zone really does have a mind of it's own?
Strelok seems to think it is in fact possible to control the Zone, and even destroy it should one wish. Who am I to argue against him, I suppose :shrug:

I kinda got the impression he made 3, the one where he got the photo and the artifact, the one where they found door and made the decoder, and the one featured in Clear Sky.

I think the Zone is probably the equivalent of Data corruption in the noosphere, and that C-conscious may have at most created psy-information viruses that are perpetuating and influencing the Psychic data corruption that C-consciousness originally created.