The GTA casino update sees not just unique GTA 5 casino missions release into the game, but also gambling games just like in nj online poker sites and some of the posh real estate in Los Santos. And then there are GTA Online casino missions: this gambling Mecca is in peril from a foxy Texan outfit that would like nothing more than seeing the whole business go belly up, and it’s up to you to stop him in his tracks. Do you know how many casino missions are there in GTA 5? GTA Diamond Casino and Resort come with a fancy interior and it looks stable and open for service from the outside.