While I think the nonsense about video games causing violence is just that, nonsense, the people who claim the GTA games glorify and actively encourage some of the most vile and despicable criminal behavior are right. GTA has no tact what-so-ever, and it's not one of those games where the behavior is purely optional and discouraged, but rather unavoidable and challenges arise from committing such acts. Not only that but the vulgarity and profanity and racism and sexism and homophobic nature prevalent in the dialog is just sickening and gut wrenching to watch. Some people think GTA some subtle satire, but there is nothing meaningful or subtle about it.
The Little Sisters in the Bioshock games are pretty disturbing. Not only are they brainwashed children made to engage in some pretty sick twisted activities involving blood and corpses, but you have to kill this monster - another brainwashed human being in an armored diving suit - who the child has been brainwashed to have an emotional bond as a father figure with. After that, in order to get what amounts to experience points, you're given the choice of "rescuing" the girl or "harvesting" her for bonus points. Yes, a moral decision that is left up to the player. Makes me wonder about the players who would chose to harvest and kill a little girl for bonus points, even if it can be seen as doing the child a favor in some back @$$wards sort of reasoning.