Pretty odd and unprofessional. At first, the interview process started pretty straight forward. It started off with a phone screen and a very easy IQ/attention to detail test. The next round is a one on one case interview via skype which is pretty basic. The final round is a five hour day with two behavioral interviews, three case interviews, and a 15 presentation on a subject of your choice. I went through the phone screen and the IQ tests which were pretty easy. Upon the skype interview though - the interview called me thirty minutes early and offered no explanation. Overall he was kind of weird and made rude and odd faces when I was presenting him with my logic. He was somewhat standoffish. I made it to the final round but the day before my interview C1 canceled it to reschedule. Nobody ever reached out to me to finish up the process and I ended up taking an offer with a different company.