So this game is pretty awesome, however the things I found most inappropriate for younger gamers is the side missions and blood.
In the side missions, serial killers threaten to kill hostages and give you a certain amount of time to save them. If you fail you see the serial killer on screen and they look rather menacing with multiple cuts, tattoos, scars etc.
The blood, in the casual street fights and mission fights isn't bad... In fact there is none. Though the other type of blood is. You have to examine pools/puddles of blood to find out who it belongs to.
There is also quite a few uses of bastard and bitch.