They give a challenge that resembles the project that you're going to work on.

Well I had a first interview, which was with HR, which went well, and I told them what was my expected salary range, and they said they were fine with that. Second interview was a technical one, which went well and I felt motivated to go on, because all the details I was given about the project and what I would be working on. Thirdd interview was with the CTO or something like that, another guy and a woman from HR. It was like 1h30/2h about trying to solve riddles because they said they wanted to know how I thinking would work in solving problems. But it seemed even they didn't know the answers to said riddles, because they were all confused. In the end, we wasted 1h30 to 2 hours in this talks, and in the end they presented me with an offer, which was below what I talked about in the first interview. In the end, I declined, because this whole process was already ridiculous, and on top of that, the offer was not the one talked about before