I thought that this was really great episode. I thought Kalin was completely and totally creepy with that laugh. It was just so intense. The way the mark was showing up in the sky was creepy too. I liked how Jack was able to see Crow and Yusei again. I was glad that they used Netherworld instead of the Shadow Relam, but that was mainly because I was hoping that people wouldn't complain about the change. Besides, I thought that it worked really well since it is closer to saying death than the Shadow Relam ever did.
I actually like the name The Enforcers. It sounRAB much more intimidating and powerful than Team Satisfication. I liked how the they all wore the same kind of jacket since it made them look more like a good team. It was nice to see how they were trying to take out all of the Duel street gangs in their area and they did a really great job with that. I didn't think that Kalin would be the leader of the group though. I would have thought Yusei or Crow would have been the leader of the group.
I guess that Kalin wanted to do something more than what the others wanted to do back then, based on what Jack mentioned, and that led him to become a Dark Signer. At least we finally got a start to this duel after seeing all of these flasrabroadacks. Even though I like Yusei's deck, it is getting a bit old seeing Speed Warrior all the time. I knew that the attacks from Kalin's monsters would be intense, but I didn't think that it would be that devestating. While I normally don't mind the puns in a series, I agree that the one at the end of the episode felt out of character for Kalin, based on what he said throughout the episode. I was really hoping that we would see more of the duel, but I do like how both Jack and Crow looked concerned for Yusei.
Overall, it was a nice episode and good way to make the duel more intense. Though, I thought that this episode had too many flasrabroadacks. Of course, it is a Yu-Gi-Oh! series, thus flasrabroadacks can always take up good chuck of any episode, and the flasrabroadacks were there to build up backstory between Yusei, Jack, Crow and Kalin, and intensity for the duel, but I was hoping that we would see more of the duel itself. I'm really looking foreword to next week's episode to see how the duel turns out.