Half recap, half re-detailing of various character arcs, these OVAs serve as a really incredible addition to a series that feels like it doesn't have enough content. Most of these are a sort of background behind each character, unlike the previous Eizo Hakusho which was pure recap. While it still retains the same incredible musical stylings of the past, if not even better, it adds a lot of additional content, or at least places it in an order that reshapes the way you would normally experience the content. Much of the heavy lifting is not done through the visuals, but rather the voice acting. The visual content is re-used, with a kind of seiyu flare to the scenes, with a more strict focus on the character being shown.
Particularly, why these tend to feel pretty decent, is because much of this content isn't actually in the manga itself. The entire final arc of Yuyu Hakusho is pretty shredded up in the manga, because Togashi didn't wanna write it, but the anime attempted to mend the broken aspects a little better, and much of this work stems from those attempts. It could be believable if these were a kind of alt-cut of the final versions we got in the anime.
