Intense, serious. Very interesting and long process, but worth understanding yourself and you know they are looking for a long term employee, not just anyone. Definitely a good experience. Be prepared for your best game and be honest.
The interview process was through. There were multiple level of interviews, several code tests, 1:1s, panel interviews.
The code interviews were pretty difficult, few time bound questions and then another refactoring test. The behavioural section was hard as well.