Games with the AO rating are considered by the board to be suitable for players age 18 and over AO-rated games can contain higher levels of violent, profane, sexual, or pornographic content than the next-lowest rating on the scale (Mature, generally considered suitable for players 17 and over) can accommodate. In some Canadian provinces, ESRB ratings are enforceable by law by local film classification boards. law, the ESRB rating system is a de facto standard which is self-enforced by the U.S. Although it is not legally binding under U.S. The following is a list of video games that have been given the ' Adults Only' ( AO) rating by the Entertainment Software Rating Board (ESRB), a United States-based organization which rates the content of video games to determine its appropriateness for specific age groups.