It looks like they're really impressed about the small details, like Niko looking over his shoulder after bumping into someone, or seeing him resting one foot on a ledge. It's some very nice little detail indeed, I can't wait to see more of those small things.
I wonder if the realism of peds will make such an impact though, some of them said they don't even want to kill them, heh. Although I'm sure it'll be very nice to see them 'living', so I'll probably keep staring at them instead of killing them, too.
Thanks for posting this, Slim