I've been rewatching Kaiji. It has one of the best anime soundtracks ever. I even downloaded the OST.
It really points out how ugly a human can be when money is involved. Kaiji itself, as a protagonist, isn't a genius at all (unlike his counter part, Akagi), he got plenty of bad default, but can be -when needed- really sharp. You can easily find yourself emotionally attached to him; you want him to win, you share his fears, sadness, etc. It's something I haven't seen in a lot of anime. Due to that fact, I'd say Kaiji is one of the most immersive series I've seen, which is rather counter-intuitive since its artwork is far from being in the realm of realism.
Also a few days ago marked the 2nd anniversary of the legendary director Satoshi Kon. Rest in peace, Kon-san.