 Phantasmagoria was heavily advertised by Sierra in advance of its release , and the company touted it as its biggest game to date . It was Sierra 's first computer game targeted to an adult audience , and one of the first horror games from any company written specifically for adults . There was no legislated rating system for computer games in the United States in place , although one was being debated before the U.S. Senate at the time . But Sierra was among several major software companies who voluntarily supported the ratings system designed by the Entertainment Software Rating Board , which rated games so adults could make decisions about software purchases . Phantasmagoria was the first game to get an " M " rating for " mature " audiences , meaning intended for audiences 17 or older , and as a result it carried a content warning on the box that said " contains adult subject matter " . The game box prominently displayed this rating , as well as a warning on the back panel that the game contains adult subject matter inappropriate for children . It also encouraged parents to review the material before providing it to children and asked retailers not to sell it to minors . Phantasmagoria also received mature ratings in Germany and the United Kingdom . 
