According to Team Ninja head Tomonobu Itagaki, Ninja Gaiden II isn't gratuitous at all, and is instead a retelling of medieval Japanese combat. Violence, he said, is about the relationship between combatants.
"Violence is not about cutting an enemy into pieces or seeing a lot of blood," he said. "That's not what real violence is. In the Japanese warrior tradition you would shame an opponent. A real sword expert would aim his slice at the first four fingers of his opponent's sword hand. This would cost a warrior his livelihood and someone suffering this wound would normally commit suicide rather than live without their sword hand.
"That's what I consider to be real violence. It's not about lopping off limbs. It is about the relationship between you and your opponent. In order to inflict these dishonouring wounds you would really have to hate your opponent and this is not what this game or this character is about."
Tomonobu. Seriously. Ninja Gaiden II's a bit violent, isn't it? The action game with the mostest releases globally in early June.