Given that Pac-Man involves a flat yellow disc consuming white dots and chasing stylised, monochromatic "ghosts", I wonder how abstract one could make a game (or an animation) for it to remain violent. If one had a primitive video game featuring, for example, two coloured squares on a black background, with one obviously "attacking" the other which (exhibiting what the human brain instinctively perceives as fear) moves away increasingly frantically, would this qualify as a violent video game? This sounds like a challenge: how much violence, aggression, brutality and other antisocial and harmful behaviour could one depict in an entirely abstract fashion, without using recognisable real-world objects or cartoon approximations?
The opposite of this would be something like a Brothers Quay animation, which includes things that look like real world objects, but whose parts move around in an entirely random and pointless fashion, not unlike a malfunctioning computer graphics program.