Chapter 127:
This was a really frustrating manga. It started quite good, mind games did feel a bit obnoxious sometimes, but the scope of the games themselves was small, so it felt ok. Characters seemed quite distinct, as well, and were progressed roughly equally. But then it was not enough. More scaled was required, I guess. It even became somewhat like "Btooom!" but without super-powers. I think some time around that time things went downhill.
Essentially the whole story was no carried by 1 character, since he was the main attraction, even though the perspective has shifted by this point as well. But objectively, you would not care for anyone but Yuichi and what he will do to solve the next big problem. Or rather you would only care to see what is the next contrived way that will be used to show him as this "genius", predicting anything and everything in a split of a second the moment that he hears the rules.
Again, with small-scale games that was obnoxious at times, but it was not entirely out of the realm of possibility. Especially with the very first games, which were only between the group of friends. When other people got involved it became less believable already, but scale was still small so it still was not that outrageous. Furthermore the storytelling itself showed more of inter-communication in "real-time". Plot twists were still "Aha! I predicted that, and you predicting me predicting!", though.
Then they went to the jungle or something, which got huge scale and here predictions became unbelievable, because... The scale was huge. It looked as if Yuichi was all-seeing somehow. What's worse most of explanations of his actions were put to the end of the game, which just made it unbelievable. And even if the scale went down in the last game... It only got worse.
Every, and I mean every, every plot twist was "something happens, group starts panicking and discussing, and then someone tells that someone has collaborated with someone behind the scenes". With no hints thrown before that at all. This made it feel like author was writing actions first and then trying to think of some convoluted thing to explain them. This also made it look like people are not even talking to each other, even though they were limited to an enclosed (for the most part) space.
What's worse is that by this time there was a strong commitment to turning Yuichi into an off-the-rockers person. Which felt somewhat out of place from the start, but in the last game it was just painful to watch. But even that it not all, because... Despite that the author went for, essentially, a happy end. Which did not make any sense. It's not real. It's not life-like. Life-like one would be a (somewhat) fatalistic ending, and not this kind of... I don't even know what to call it.
In short, if you start reading this manga, I would recommend you to stop it after the first game series ends. Protect your brain.
