The ESRB has only ever given 2 games the AO rating solely for violence. One being a distasteful mass shooting simulator (Hatred), the other being an unreleased fighting game focusing on Fatalitites during the ESRB's infancy 20+ years ago (Thrill Kill).
So would I be safe in assuming that I can cram as many red pixels as I can into a 48x48 grid, so long as the violence isn't sexual in nature, and so long as it is not an attempt to inspire controversy?
I only ask because I'm a graphics artist and the idea of trying to gross people out in a pixelated horror game sounds like a fun challenge.