tl;dr: A manga that has well thought out games that serve as exciting battles of wits, but that is severely lacking in every other area.

How much you enjoy this manga really depends on what you want to get out of it. The overarching plot is mostly nonexistent beyond hints here and there for the entire manga, and though it does finally get revealed in the end its just kind of thrown out there in a rushed manner and ultimately I wouldn’t say it has much value. There are characters that are interesting and the two leads, Nao and Akiyama, both have character and relationship development. However, that only matters as far as the games are concerned, and beyond that it doesn’t really have much of an effect at all, it really not mattering in the ending at all. So in terms of anything overarching the manga isn’t just weak but pretty much completely empty.

What the manga does have and what it does incredibly well are the games. The manga has a very simple structure of characters participating in game after game with pretty much nothing in between. Characters carry over from game to game so their personalities, their relationships, and their circumstances do play an important part, though as mentioned they only play an important so far as the effect on the games themselves. Beyond that none of these aspects are developed very well. Now as for the games themselves, they’re all incredibly well designed, with a good amount of complexity and depth, depth that gets explored incredibly well both in terms of the base mechanics of each individual game itself. But more importantly depth in terms of manipulating others in order to guide them to perform actions that along side the game mechanics result in the desired outcomes, which often ends up completely changing how the games are meant to be played, sometimes even changing the goals of the game itself.

In addition, each aspect of these is explained in incredible detail such that even though things can get fairly complex at times, things never get confusing. The argument could be made that it over explains, but it’s a written work so it's easy to simply quickly gloss through the explanations that are unneeded so I didn't find that an issue. The manga also does a really good job with framing during the games, where it changes perspective quite often in order to control what the reader knows about the current state of affairs while guiding them to think of the games flow in certain ways similar to the character the perspective is currently under, only to shatter those expectations with a major twist that then goes on to be explained in detail. It was both exciting and suspenseful throughout, and the victories during these games were quite satisfying.

Hence, even though the actual ending in terms of plot, characters, relationships, etc. was incredibly weak and not satisfying at all, I’m overall pretty satisfied with the manga. The art was pretty average and dull overall, but was really good in terms of using diagrams and such to explain things which was the most important part.