The ESRB has recently announced that Ar tonelico Qoga ~Knell of Ar Ciel~ has been rated Mature. All previous Ar tonelico titles have received a Teen rated due to suggested themes, partial nudity, and language. Ar tonelico Qoga ~Knell of Ar Ciel~ takes this one step further as mentioned in the following description from the ESRB: "Battles are accompanied by punches, kicks, colorful light effects, and loud cries of pain; enemies collapse or disappear in brief flashes of light when defeated. Some power moves cause female characters' clothes to vanish in layers; the characters are often depicted holding (covering) their breasts, wearing only underwear, or standing behind strips of light that obscure their genitals."

Ar tonelico Qoga ~Knell of Ar Ciel~ is set to release on PlayStation 3 sometime March 2011. If the game releases in its current form, this will be NIS America's first Mature-rated game.