The violence and gore is not graphic most of the time. It is rather abstract and surreal.
A man is stabbed, blood is shown.
A boys hand bleeds a lot from being wrapped around a metal wire.
Many children are seen being killed, this is not graphic but rather abstract. No blood or peril shown.
Near the end of the show characters are seen being cut by glass shards, the blood is shown as a red penguin in the shape of a rose petal. Abstract, not graphic.
A woman shoots ping-pong like balls at people, the ball explodes on the persons head but it does not cause harm, it removes the targets memory. Not graphic at all.
References to the 1995 Tokyo Gas Attacks.
A teenager is kidnapped and tied up, being threatened with being burnt with a blowtorch.