S.T.A.L.K.E.R.: Clear Sky - Interview @ RPS

Rock, Paper, Shotgun chats with GSC Game World's Valentine Yeltyshev about Clear Sky:

Great. And there’s all the new stuff with Factions, right?

VY: Yeah. We’ve got a new storyline with two layers. On one you can be completely free. You can join any faction that you want, do whatever you want, and progress through the main story however you see fit. But on another layer there is the completely unscripted story of the zone. The factions, using AI, will be battling across the zone to capture territory or engaging in skirmishes – it’s completely unique to your game and you can take part, or not, as you wish. You’ll have complete freedom in the game to do whatever you want to do – you could even just join a roving group of bandits.