Hatred has received an Adults Only rating from the ESRB.
Following Valve’s decision of bringing the game back into Steam Greenlight, and then approving it, this is potentially a serious setback to the game’s release. Adults Only rated games are usually refused sale in the biggest retailers, and usually leads to adjustments in game content to fit ESRB requirements for Mature games.
As you can see from this list assembled by GamesRadar, the big majority of Adults Only games are literally pornographic games, either FMV or hentai. There are also several mainstream games which received this rating, each of which courted subsequent controversy.
Grand Theft Auto: San Andreas’ retroactive ratings change from M+ to AO meant Rockstar had to pull the game off shelves to remove the Hot Coffee mod. Seduce Me briefly made a splash for being pulled off Steam for its content. Leisure Suit Larry: Magna Cum Laude and Fahrenheit/Indigo Prophecy were released in both Mature and Adults Only editions.
Most relevant to Hatred is the precedent set by Rockstar Games Manhunt 2, which initially received adjustments to be sold in a Mature rating, and then was briefly sold in an Adults Only edition by online digital download service Direct2Drive. D2D was the only platform willing to host the AO edition of the game, and they eventually pulled it from listings when they were bought out by Gamefly.
If Hatred’s developers have no plans to change the game content to reach that Mature rating, they will have to find platforms willing to host Adult Only games. Based on their decision for Seduce Me, Steam does not seem to be that platform. Of course, they may also opt to sell the game on their site if it came to that.