Every interviewer brings his own personality. Most people(probably all) will stay to-the-point. Actually the more to-the-point they are, the more time I get to solve the problem, so that's kinda by design. Emphasis on behavioral stuff is near zero. But a couple of people asked me questions related to stuff on my resume. E.g. one interviewer asked me a VHDL/Verilog related question(I think of it as a sanity check question, to make sure I'm not BSing on my resume), the other had already asked me two questions, so he used it as a topic of chit chat. Some interviewers are poker face to the point that you feel the pressure, one interviewer wasn't big on hints(at one point I could hear the wall clock ticking so loud, I wanted to throw it on to the floor and smash it), one interviewer liked to make encouraging comments and was somewhat chatty. The others were like just any dudes you might run into at a party, very casual.
The CS/Coding Questions covered topics like Dynamic Programming, trees, arrays, bit manipulation. The questions were not easy. I think I did ok in 3 of them(one/two might be even slightly below par). The Dynamic programming question I solved in 15 minutes, then I got asked a second question(which was easier in my opinion) I finished that too and I still had 10 minutes left. I imagine I impressed that interviewer. That might be the reason I got through.
The system design question was a very interesting one, I loved it. But it wasn't your typical large scale system design question like designing a service and so on. It was about designing a file system. I enjoyed it so I thought I did well there. Since I seemed to have talked all I wanted to about that question, I got asked a second systems question(in the same interview), an open ended question about internet system. I did ok in that one.
I didn't ace most of the interviews(Dynamic Programming interview being the exception). I thought it could go either way, since Google has a reputation for being very picky.
I had put some time into preparation this time. Friend of mine is coaching for interviews, so he provided me very well defined structure to focus my efforts, including videotaped mock interviews and feedback on it( interviewkickstart.com for anyone interested. Highly recommend!). Through the mock interviews I realized that I was talking too much, both in behavioral questions and during problem solving. Not only could that test the interviewer's patience, it also meant I had less time to solve problems. So I had to strategize about that. I think that helped me go that last mile.
Lunch interview was very casual. The guy was very friendly and liked to chat. I asked him whatever I thought I should about Google and the people there. Got some insight into Google that way, even though I know friends who work there already so I could have asked them anything.