I love this show so much! I never thought I'd be hooked into a german sci-fi show like this. This show starts slow but as the time progresses, it's gonna mess with your head.
This show is heavily influenced by Nietzsche's work and the time is not linear like the Back to the future and has loopholes like that of Endgame. The time factor is based on Einstien's 1916 paper on Relativity. It includes some of the famous paradoxes like a bootstrap paradox, etc.
This show is possibly the best Netflix show available imo. This show is for smart ones, not for some random teens.