They simply look for pepole to work. Company is trying to make impession of good employer and be selective. My .NET skills were thorougly tested. I accepted the offer only because I was looking for first job and didn't know much about industry.

Had relevant questions regarding .NET: everything starting from experience and finishing with theoretical questions. I was interviewed as a middle .NET engineer. Most set of questions were related to: SQL and databases, .NET development, security (OWASP), design patterns and principles, REST API, etc.