While Yu-Gi-Oh is still going strong with the card game still ongoing and new anime series being release, it's interesting that I one day learned of this incarnation of Yu-Gi-Oh! Basically, the series we Americans started out with was not the first anime series for the franchise that would be one of 4Kids' popular dubs (as well as the one that got into legal trouble and eventually into bankruptcy), but this is the first one, an anime that was never dubbed, and for good reason.
This anime (referred to by fans as Series 0 or Season 0) is based more on the manga, as the card game the franchise is known for is not the main focus. Instead, it is about Yugi building the Milennium Puzzle, but in doing so, he awakens the spirit of a pharaoh who takes over his body when he or his friends is in danger to challenge bullies and criminals with Yami Games, where losing or getting caught cheating is punished by a grim fate (although the grim demise is actually an illusion that ends up breaking the villain of the episode mentally). Yeah, this is reason why this anime was never localized: other than not dealing with the Duel Monsters card game that the franchise would focus on (even though it featured in some episodes), the anime was dark and violent to the point where 4Kids probably decided that no amount of editing can tone it down for the company's target audience of kids like Yu-Gi-Oh! Duel Monsters was, despite the fact the series' violence was already toned down from the manga it was adapted from, as here, Yami Yugi is more of an anti-hero who punishes people instead of the noble pharaoh who, in the 4Kids dub, would lecture some villains about the folly of their ways and the heart of the cards, although he does change his ways near the end of the series.
While the anime is good, it does have some flaws when compared to the manga. Being at only 27 episodes, most chapters are not adapted, and a minor character from the manga, Miho Nosaki, who was only in one chapter, was promoted to a main character here, and sadly, some people has claimed her to be annoying and only being there to mess up, so chances are whether or not you'll like the character will be based on how you can handle her actions. While the series was never localized, Yu-Gi-Oh! Duel Monsters did adapt some scenes for flashback sequences to explain some events (with some stuff changed), but this is a neat curiosity to check out.