Can you chain saw people as locusts in multiplayer? I've honestly only played it a few times and I'm usually dieing by bullets (I'm quite bad at it >_>).
Also, chainsaws alone won't get you an AO rating, just look at RE4. In the case of Manhunt 2 it was the fact it was senseless violence against innocent people in pretty sick ways plus the game was just about that added to the AO rating. Rockstar knew what they were doing and it just blew up in their face.








