A new developer diary has been posted by GSC Game World, following up on the game's E3 trailer and providing some more detail about what exactly we were looking at, as well as revealing a couple of easter eggs.
GSC's Zakhar Bocharov talks about the gunfight at the bandit's camp seen in the trailer, and emphasises the new animations for installing weapon modifications on-the-go. This is something of a minor theme in the video, as it later returns to the (highly impressive) NPC animations and shows some of the motion-capture and facial technology that went into creating this look.
Bocharov also says this scene teases a new faction. Fans reckon this is referring to the graffiti seen near the beginning of the segment which apparently includes the Ukrainian for 'guard' (timestamped trailer here), suggesting a military faction opposed to the known bandit faction. Furthermore, Bocharov points out that a location seen in the trailer, featuring a heavily-leaning tower, is a location from Stalker: Clear Sky that's been further ravaged by time.
The new detector seen in this scene is named after the Ukrainian term for a branch or stick, 'gilka', thanks to its visual appearance, while the artefact that protagonist Skif collects near the aberration is called jelly, and recovers your stamina.
Perhaps the sweetest little detail, however, is a cameo in the campfire scene at the end of the trailer, as seen here.
As Skif gets up to leave for Pripyat, this man grabs him and says "good hunting stalker." Turns out that this is no less than Sergiy Grygorovych himself, the founder of GSC Game Worlds and creator of the series. Good hunting to you too, GSC, and please bring us all something from the zone to treasure.