This interview was the most time-intensive interview of my career. Mantra asks you to complete a take-home exam as well as a full day of interviews. Overall, I spent a lot of time preparing for and doing this interview. When I got to the end, the CEO explained to me that the position would be scientist for me, and not senior scientist, citing that I did not had too few years to merit Senior Scientist. I feel like they really did a bait-and-switch tactic here: I would never have put in such an unreasonable amount of time and effort for a scientist position. They had my resume before the interview, they knew how many years of experience I had. However it was only after interviewing that they changed the position I was applying for. I discontinued the conversation as soon as the ruse was made apparent. Also be advised they will flat-out ask you solve their current technical issues as part of the interview. Don't do what I did and give them free consulting.