This rating indicates the game contains almost nothing that would be unsuitable and\or inappropriate for minors under 12.
This rating indicates content suited best for anyone ages 12 and over.
This rating indicates content suited best for ages 15 and over.
This rating indicates that the game contains some adult content and therefore minors must get permission to get games with this rating. And it's recommended that you are 17 if you play any game whit this.
This rating indicates content ONLY for those ages 18 and over. Nobody under this age can purchase the game.
In addition, cultural factors unique to Japan have caused discord among this series. Some games have gotten A's here but received Mature (17+), while on the other hand, some games are getting Teen (13+) here while getting a Z rating in Japan (I.E. Infamous).