This was kind of a frustrating arc to get through, and not because of it centering entirely on a variation of mahjong (though that was certainly part of it, and I'll get to why later--I promise the reason isn't just "I don't get it") but because of all the conflict, themes, and plot points it presents that it sort of falls short of meeting expectations.
First, the arc starts off pretty amazingly. We see Kaiji after all his debts are paid, at first under the assumption that after the last arc he'd be on the road to success, only to see he's at a possibly even worse state than he was before. He's depressed, unmotivated, and lost, still disconnected from others, even as he resides in the house of one of his friends. It's a pretty sad, brutal sight to behold, even moreso when Sakazaki puts it into perspective after Kaiji tells him he plans to gamble (his true calling) again.
Then the gambling begins, and it's nothing too impressive so far. Then Kazuya gets introduced, and things liven up a bit with Kazuya giving Kaiji hints of what his fate will be if he loses this match. Then they slow down. Then Kaiji comes to a realization that the friends he thought were on his side are his enemies now, and then the arc really begins to pick up. We get insight into Miyoshi's mind and his heartbreak over Muraoka "proving" Kaiji isn't the hero he thought he was, driving him to betrayal, then (and here's where I may be getting the events out of order) Kazuya brings out a device that will force Kaiji to bet his limbs should he run out of money, then Kaiji puts two and two together that Kazuya is the son of the chairman (a reveal I knew beforehand that still had me jumping back from my screen), then Kaiji calls out Miyoshi and Maeda, ending in all of them firmly unable to trust each other, then we get a look into Muraoka's mind and what got him to where he's at now, and then...!
The pace sort of slows down again as the game resumes. Kazuya's device (the spinner) is never brought out again (one of the biggest letdowns, as it would have added on some great tension). We don't get any more insight into Miyoshi's mind as everything is unraveling before him and Kaiji's life is put on the line (all "LET'S KI--" line from the second season anime joking aside, I sincerely doubt he was thinking "He deserves that too," as he was really only in on Muraoka's provided Kaiji would just be losing his money and nothing else; if I had to guess, he was probably desperately thinking Muraoka and Kazuya were over-dramatizing it as they always do). Miyoshi and Maeda are mysteriously absent as their boss breaks down from his loss as Kaiji wins more than just his money, but his house and property as well.
The final hurdle isn't void of its amazing points, of course--the way Kaiji wins is as brick-shittingly awesome as it was in the previous arcs, Muraoka's breakdown is great, Kaiji's parting words with Muraoka are great ("Hey, you still have your casino, right? You just have to take it a step at a time, right?" or something along the lines), his interaction with Kazuya is great (I especially like how he described and admitted that he and his father were both fair people), the final pages were great...but it wasn't really enough to make up for the highly significant plot/character threads that got cut so short, and while I hate to harp on the mahjong, the gamble prevented this arc from hitting that sweet spot as well (because while the story absolutely can be enjoyed without knowledge of this variation of it, being a clueless passive observer of the same game can get old after a while, even when you get the gist of what's going on).
This wasn't a bad arc by any means, it was surprisingly quite good (and, again, amazing at the points I bring up). I just missed that sort of...for the lack of a better phrasing, sense of emotional roundedness? That the previous two parts had, which was surprising given the conflict and subject matter at hand in this part.