WARNING: SPOILERS BELOW
Second season doesn't deliver. At all.
I was hoping for more great mindfights between Kaiji and his opponents, and only the Chinchiro part was about that, the rest was mindless fillers of Kaiji waiting, Kaiji shouting and Kaiji crying. It really should have been a 13 episode anime, because it needlessly stretches out everything.
The story wasn't too terrible, I enjoyed seeing how Kaiji will defeat Ohtsuki, how will he get the money for his debts and how will he work out the way to win at the Bog. However comparing this to the first season it's pretty lacking, and towards the end you get about 4 episodes of pointless talk and waiting.
And remember how Kaiji wanted to destroy Hyoudou in the first season? There is absolutely no interaction between the two in this one. They don't even meet.
Animation wise, it was great. On top of the great art style, everything moves smoothly. The 3D animations are as good as, or even better than in the first season.
As goes for sound, neither the opening nor the ending was catchy. And overall, the soundtrack was pretty bland, and not rememberable.
And for characters, I have mixed feelings. Kaiji doesn't show any change nor progress at the end. He got fucked over by Endo, and he still insists on saving his "friends" from the Undergound, and after saving them, he blows all his remaining money on a fucking pachinko. My guess is the author wanted to show him as a total loser.
Regarding other people, I'm sad that there was no interaction between Kaiji and Kurosaki, like with Tonegawa before; Ohtsuki and Sakazaki were nicely presented and Ichijou impressed me by his gradual change from a villain to a person similar to Kaiji, who was about to live or lose everything.