The process started with a recruiter, and the initial discussion with their COO was quite pleasant. However, despite the position being advertised as full stack, they were really looking for a front-end developer. This was reflected in both a later conversation with the recruiter, and also the interview. They waited until half way through the final interview to do a tech screen (which is normally one of the first steps in the process). They ask you to complete a coding exercise, which that part of the process is really well done and open ended, in a good way. However, despite approving of the code and a cultural fit, they used the on the spot pop quiz as the basis for their decision. This says a lot more about them as a company than any candidate. If the tech screen is that important to the decision, then it should be done much earlier in the process, or at the very least the candidate should be informed so they can prepare.