The steam game ARK is a fabulise open world survival and adventure game. It is rated 16 but only because of the really good graphics. In this game your task is to survive a open world full of extinct animals (Not all). Compared to most games this is can be pretty hard core if you set it so.
My personal rating on it is 4.5 out of 5 because of the graphics, the sense of danger, mystery and excitement. if you are good enough you could walk around riding a rex as you murder everything in your path. however the game is meant to not be easy, you could be stormed by a pack of dire wolves or a carno and end up dead and loose everything, which if very frustrating.
I hope you found this helpful, I really suggest you buy this!