Lots of shooting. No one gets killed (except by accident, frustration or intolerance for sarcasm). Unless GLaDOS is serious about that "android hell" thing....
Did I mention droll? Lots of games start out this way. I'm upbeat to believe Portal 2 ends as well as it started, considering the original Portal's track record and that viral video about being still alive.
[Aperture Science Sentry Turrets] have all been given a copy of The Three Laws of Robotics to share. (N.b., gotta love it! Any game that can devote a few precious nanoseconds to set phasers on KRILL and twig off the biggest horse's ass in last century science fiction has my gratitude.)
You seem to have packed on a few pounds ... Waddle over to the elevator and we'll continue the self test.
Just remember what I said just now [speeded wa-a-a-a-y up] in slow motion.