But I don't think that's a good rating for the game, because it's very dark and deals with some pretty serious issues that would either alarm a ten year old kid or go over his head completely in a somewhat unhealthy fashion. Granted, I've met some very mature ten-year-olds, but on average...
Actually I think giving children access to more mature themes in video games would be for the better. The general culture that children live in is quite bright and pink and blue which results in these carefree 'not very mature' characters. And this is fine, a happy childhood is great. But as they said in Ed, Edd and Eddy "A little childhood drama builds character."
Final Fantasy 6 was pretty good at this, I myself was 11 or 12 I think when I played it. You have these characters who are fun and exciting and you have this adventure storyline and as a child it is quite easy to connect with the silly epicness of it all. Then every now and then you are faced with these dramatic events which change the tone of the game to something quite serious. Suddenly start to feel with the characters on a different level, building empathy and all that. You generally become a better person for the experience.
Of course the latter Final Fantasies went beyond all taste with this.
But have a kid play Cave Story and they will connect with it even more when Curly dies.
(and to be a real bastard tell them they could have saved her)