If you're okay with some very black comedy (all spoken-aloud, nothing shown) and the occasional blood splatter when you get shot, the Portal games are good. The villains are robotic turrets with machine-guns that are defeated simply by tipping them over - so while they're acting in very violent and lethal ways, the player is just teleporting around and nudging them over to fall down onto their side. But I remember my kid being very offended when GlaDOS called the player character fat, and later reveals she mass-murdered a building full of scientists using nerve-gas.