I've read this book around four times.
It's a slightly more than average book.
I love it anyways.
For starters, children must understand that what Artemis does is wrong and that he ends up paying for it.
Ha-ha, Artemis. Ha-ha. (Please ignore that)
Anyways, the violence is not much, but if you prefer for your child(ren) not to be exposed to literature with shooting and guns in it, then this isn't really recommended.
Unfortunately, my memory must be horrible since I can't recall anything else that is inappropriate in this book...
(Oh, this book is slightly childish if there's any adults out there trying to see if it's worth it. I like the first book better. It's more interesting and I recommend that, but not this one. Then again, this series isn't aimed much at grown-ups....)