Before watching this episode, it is mandatory to watch episode 0. I honestly haven't played either Berseria or Zestiria, so my review is based purely on the anime-only perspective, I would eventually edit the review once I played both the games. Even after watching this episode I'm still full of questions but the curiosity itself is what drives me to keep on watching. Aside from that I don't have any complaints on Ufotable's exceptional animation. If I'm not mistaken the segment after the ED looks like it's something from the game itself which is a nice touch.