First round with HM was amazing, very nice guy.

Went very deep into technical; I couldn't answer a few things, but he was very encouraging. At the end, I asked for feedback, and he gave me an honest answer.

He basically covered the entire resume, asking questions from Master's courses. The entirety was focused on role-specific background questions.

The second round was Director level. This was the round that was awful.

The Director seemed to expect me to be as deeply prepared in every aspect of my resume as the aspect that was relevant, and naturally, I couldn't answer one of the first difficult questions he asked me. He instantly looked disappointed and as though I was wasting his time.

When I stated some facts about myself, he looked surprised and annoyed, like he hadn't debriefed with anyone about my candidacy. The interview got progressively worse, and 25 minutes into a 1-hour interview, he concluded it and rejected me.

Thorough questions from resume, asking "why?" and "what if?"

Extremities of the process. For example, I worked on CVD at 1050°C; how would it react at 1000°C?

Alternatives to tools I used and why my tool was better for my purpose. For example, I worked on SEM. Why not TEM or Optical for my application? SEM vs. TEM. Limitations of Optical microscopy.

The HM round had situational questions and behavioral questions as well.