One of the thorniest problems is not being able to enforce the family rules outside the home though.
Parents can refuse to buy games such as 13 plus, 15 plus etc in a kids own home, but often he will be exposed to 18 plus violent games at friends' houses.
Worse, his own games will then seem tame and not cool. It helps if similar groups of parents enforce the same standards.
The word 'assasin' seems to be popular and used a lot - really, what could be worse!