The interview was more based into motivation of joining the company and some brief talking about past experience. Some talking about technology stack they use and the methodologies on how company works. Overall the conversation was fine and they look like kind people but they decided to not move further due to other more fitting applicants. I don't actually know how they decide for the best fit or what strategies they use to filter applicants, but deciding for it on the first round seems not legit to me (at least if you are searching for an engineer).