Two video calls with upper management, followed by a take-home assignment that had to be completed in 32 hours, and finally a lab tour and 5 face-to-face interviews. While the video calls were fairly casual, the take-home assignment and face-to-face interviews were hard -- the latter being an entirely behavioral interview (almost no questions about my resume or past experience). I felt that the right answers to a lot of their questions depended on study goals and variables and on the testing constraints, and I was not told what these study goals, variables, and constraints were (see example below). Providing a bit more context before asking questions would have resulted in a much more useful and objective interview.