First interview 30 mins with a senior dev, went great. Then a take home task, spent over 10 hours on it and received no following answer, not even a confirmation. Very disappointing

The process consisted of an initial interview followed by a simple technical test and then three additional interviews each with a different focus (Technical, teamwork, and business). The technical test was a classic and straightforward linked list test in C++. They encourage the use of any C++ library if required. You can complete the test with no time limit and without anyone watching. Overall the interviews were casual and well structured. All team members that I spoke to (8+) seemed nice and most questions were easy to understand. The reason my experience being rated negative is due to the rather ironic feedback that I received. In the final interview, it was stressed that I'd hear back within two days with either an offer or a rejection with detailed feedback. I never heard back from them directly but instead needed to call the recruiter after not hearing back for over a week. The received feedback only said that they felt my answers were "too vague". After four hours in interviews and over three hours completing a technical test, I find this feedback not only useless but insulting.