I've had Lynx Casino for years. It's the only "gambling" title for the system and a bit on the rare side. It has decent versions of Blackjack, Craps, Roulette and Slots.
And character. Or really characters. Odd people wandering around the casino that you can briefly interact with. Throwaway bits of humor but I think it's a nice touch. The control of this game is decent, and while its fun to wander around a bit, like a real casino, the play is decent.
Caesar's Palace is basically the same game on the Genesis. You can wander around, but no characters. And the controls are aweful. Playing the games is slow, and it's easy to make mistakes with the controls.
There are more games — I think Keno is an odd addition, basically you go over to a keno station, fill out a card, and a little while later while you're playing something else you're told of the results. About as much fun for me as real keno, which is to say not at all.