The first two rounds (phone interview and online test went smootly). According to their feedback I have failed on the in person numerical test which I do not fully believe.

After an online application process I proceeded to the 1st round, that indeed takes place at an open office environment where you are left alone at a laptop with some awful online HR evaluation software for 30 minutes. Not good, but have seen worse. 2nd round was a face-to-face meeting with the head of HR. I've got a few typical questions about my motivations, background, and my future self, but in the second half mostly guesstimation questions were asked, with the goal of evaluating ones logical skills. It was a long interview -took almost 90 minutes-, but they were all very nice to me offering water and such. Unfortunately I failed the last question where I couldn't come up with a correct solution, but overall it was a good experience. Only bad impression is the looks of their office. It's all new and stylish, but the dark colors make you feel you are in a bat-cave. Any architect would advise against picking their company colors for interior spaces - that really is the only (but very important) reason I'm happy I did not get hired.