The first interview is a series of basic, standard computer science and tech-specific questions. It's an old school style of interviewing that is easy as a candidate if you skim a few computer books in advance or look up common software interview questions. However, this interview style rarely provides genuine insight about the candidate. I've worked with so many engineers that can ace this type of interview but are terrible engineers. There were also several red flags so make sure to ask detailed questions about their culture and current technology stack to make sure it's a good fit.