This episode is one that solidifies many of the themes of the show, such as casual determinism, free will or the lack thereof, wormholes, duality being incorrect, the triquetta, and probably more. Though the symbol of the triquetta was shown much earlier (episode 2 or 3 iirc), this is the first time we learn about it. It's also an important set-up for events that are yet to happen, and it's a very cool experience to view this again after watching all 3 seasons, and knowing why certain characters are doing certain things. There's a couple scenes that wouldn't even have meaning the first time you watch this. Oh yeah and there's the dark scene that was quite shocking and demonstrates that Dark doesn't hold back, while also perfectly feeding into many of its themes. I also have to mention the music montage scene is great in this episode just as every episode. Slow character-focused scenes without any dialogue and with perfect accompanying music is powerful and masterful storytelling and is one of the main reasons I regard the show so highly. This is a great episode of Dark that has a little something for everyone.