I let mine 5 year old son play this game because he sad he liked game and want very much so I buy game for him but little later

I let mine 5 year old son play this game because he sad he liked game and want very much so I buy game for him but little later he come to me and say "daddy this game much scary!!" | look at game and it say: "ZOMBIE EAT YOU BRAIN!!!" and me was shock. how can this game be allow for childs? this game has blood and violins, zombie eat your vegetables!! zombie may no eat vegetable, my son eat vegetable!! he is now life shock and he have to take pills everyday!! tanks so very much electric art!!! this game much bad and scary, I rate 16 and over!! not play this game, this very innapropait!!! u has been warninged!!!