Generally speaking, love is not good for body and mind, and violence is only harmful to a few people. Because children can still distinguish fantasy from reality, however, only some particularly naughty children imitate violence. So love is harmful, because this kind of game is usually a story that takes place in school. Children, especially girls, may often fantasize about that aspect, and playing too much may lead to mental illness.
There is also horror, some horror, such as paranormal games: NDS games: never watch, seven days after death, Silent Hill. Children with poor psychological endurance or rich imagination may cause mental illness after playing this game, such as thinking when they are alone.