Manhunt 2 most certainly wont be released in the US on 10 July as it currently stands, as both Sony AND Nintendo do not grant licences for games to be released on their system if they have an "AO" rating.

Which is why for a period of time San Andreas was withdrawn from stores, because when the "Hot Coffee" controversy was going on, the ESRB re-rated it AO and as such it wasn't allowed to be sold. So Rockstar had to completly remove any traces of the Hot Coffee code for it to be re-rated M and allowed to be back on shelves.

So although there's only a years difference between M (17+) and AO (18+), because Sony & Nintendo wont grant licences to AO games and retailers wont stock them, it's essentialy the difference between a game being released or not.