This is not a serious company.
They seemed biased against people who did not work in a start up environment before. They suggested that these people are not used to performing their job fully(?). The recruitment process had plenty of interviews and tests. The last interview consisted in a one hour presentation which required extensive preparation from my side. I was very disappointed when the participants came late to the interview, cut off the time allocated for my presentation on the spot and artificially played a very grumpy customer that was not interested in the presentation.
Then, they requested references before an offer, stating that the team's feedback was very positive. They insisted to speak to my current manager and to know when I could start, without any official offer. I gave them a different reference to speak to instead. Then, a few weeks later, they called to tell me that they had given the position to another candidate, "because they had plenty of candidates to choose from anyway".