Tamer than live-action, but still moody, violent.
Parents need to know that this is a more mature Batman cartoon than the ones they might remember from their Saturday morning-TV childhoods. There is real death (including a parent), much violence -- even if it's animated -- involving explosions, guns, knives, etc. There's even some unsettling imagery involving corpses and the Joker that may upset the youngest kids. Anyone unfamiliar with the Batman saga might have some trouble following the story.