I actually interviewed for two different positions at Google with very different experiences. Both times it was a referral from a Googler who I had met socially and got interested by my background and skills. One set of interviews was for a management position. After the HR screening I went onsite for an afternoon of interviews. 6 total. This was pretty exhausting but I enjoyed very much the discussions, all questions were situational and directly related to the position. Good experience overall. The second time was for the PM position. (my current role is director of PM). After the HR screening I got an interview with a PM who arrived 20 minutes late and it did not go well from the get go. I was interviewing for a position in the enterprise business part of Google. Enterprise software is my background. The interviewer was a pure consumer software guy. There was just too much of a disconnect. I could not handle questions about the market size of wearable devices and he could not answer my questions about the competitive landscape between Google and Amazon in the enterprise business. Pure waste of time for both of us. Google is a very successful company so obviously their process works. But I know they struggle in the enterprise space and I understand better why.

Very self-driven, first of multiple rounds, where I had to take the initiative to arrive at the problem, constraints, approach, solutions, tradeoffs and reasoning behind it in a matter of 30 minutes.