Grand Theft Auto: San Andreas
Drug dealers, robbers and street walkers made this game controversial when it was first released. Programmers found later on that a certain code could be added to the game to make all the characters walk around nude. The code was made available to the public through the Internet, thus the adult rating.
Resident Evil 3
Full of horror movie action, Resident Evil 3 is considered adult because of its gory action. Zombies attack a city and are around every corner you come across. Shooting the zombies multiple times in the head and in the chest are the only ways to kill them. Resident Evil is one of the few games rated as an adult game because of the gore and constant action.
God of War
God of War is a role-playing game where you play as Kratos, a Spartan who is mad at the Gods and kills everything in his path. Rated M for mature audiences 17 and up for blood and gore, nudity, violence, language and sexual themes.
Indigo Prophecy
Rated M for mature audiences 17 and up, Indigo Prophecy is considered adult for the language, violence, alcohol and tobacco content. Three different story lines run through this game, as you play three different characters. The troubles encountered througout this game lead to violence and strong language not suitable for children.