The ESRB has asked the publisher of Wartunes to halt a marketing campaign that makes use of the board's adult rating.
Games Industry International reports the ESRB has not actually given the game a rating and even if it had, the marketing campaign would likely come up against adverising guidelines.
"We have advised the game's publisher that they must discontinue their unauthorised use of our AO rating icon in its marketing," said an Entertainment Software Ratings Board representative.
The ad features a barely dressed angel next to the ERSB's tradmarked "adults only" logo, with the tagline "adult gamers only". The Wartune's name itself gets relatively little space.
It is unclear which company the ESRB contacted, as the game - developed by 7 Road - is currently distributed online by several companies including Kabam, Kongregate, Armor Games, NGames, R2Games, and Proficient City Limited.
"While it's fairly rare for a game to self-apply a rating we will always move quickly to address the issue," said the representative.
"Our goal is, of course, that they immediately stop using the rating. If a game is digitally distributed, we also encourage companies to use our Digital Rating Service, which is fast and easy and assigns ratings without the developer having to pay a fee."