The interview process is somewhat brutal. After going through a telephone technical screening, I interviewed with five other employees; one interview was a casual lunch interview, but the remaining four were highly technical.
Pyrofex tries to tailor questions to the interviewer, and to try to disprove first impressions. If someone seems like they are good, try to find something that they struggle with -- if someone doesn't seem like they would be a good fit, try to find a way they might be, etc.