An HR employee found me on LinkedIn with information about the job, and we had a short Skype call as a first screening. They invited me to an interview in their office with their CTO, head of artificial intelligence and a computational linguist. They asked only a few questions about my background and quickly went into small tests about solving problems, wanted me to have technical details to the solutions off the top of my head. They seemed unimpressed, but sent me "homework" to complete and send back. They then invited me for a third interview, which was less structured and more specifically about whether I had ideas for how to help them. They sent me an offer a few days later, after which I sent a counter-offer. They more or less agreed to the counter offer by email, but never sent a new offer despite my reminding them a few times. The whole process seemed a bit improvised and unprofessional - and the ghosting at the end was really inconsiderate. But at that point even if they had sent me the revised offer, I'm not sure I would have accepted it.