I got a take-home task that had pretty strict time limits (4 days) and also quite a lot of requirements. One of the requirements was to use quite an obscure java web framework (not sure I can name it but the name starts with an R and ends with a K =)). The framework was completely unknown to me and had a complicated DSL so I fumbled a lot initially, trying to figure out how things work. I also didn't know which UI options existed for that framework, so I spent extra time doing discovery on that and trying different options. They weren't well documented and even StackOverflow was not much help. After trying a sparsely documented option and barely making it work, I gave up and just went with an FE React application that I could at least produce quickly enough. Due to so much lost time and the steep learning curve, I didn't make all the requirements - I missed the UI tests and also some of the functional requirements that as I said were very particular and detailed. I was very aware of it, and kinda prepared to take no for an answer after reading one of the interview reviews here on Glassdoor where an author was in exactly the same situation. So I wasn't surprised when the answer was a no. I also wasn't surprised that the feedback was read to me by an HR person and throughout the whole process, I was yet to meet anyone technical. The HR person was very nice and sympathetic and very well aware of the interview process's drawbacks. They took my feedback and told me they were actively trying to change the process. I hope they succeed because I was actually very sorry to have missed this opportunity. Developer productivity is really interesting to me since it's catering to us engineers as customers, and I also hear that despite the draconian hiring process, it's a great place for engineers. Well... perhaps next time. I did give it my best shot though. I spent every waking hour that I had free on it and sent it over at 3 AM on the day of the deadline. I don't even know how many hours it took, but it felt way over the declared 12. So I can't say I failed for lack of trying. If I failed, I still did my best. Just a note - I am a senior engineer and have been coding professionally for 20 years.