ARK is an incredibly fun game involving dinosaurs, co-operative play, survival, and a thrilling story that you pick up as you play. The base game is a bit rough as it isn't a game that holds your hand in any way, nor is it designed for solo play. If you play solo, just bump the stats till it plays as you want it, otherwise you'll be playing a 15 person game by yourself! If you use mods for stacking and building, then the game is wonderful and nearly flawless. Only real complaint is the game devs keep coming out with new stuff without ever fixing the small issues and bugs from the original map, though console commands can help you with whatever is wrong for now.
If you like dinos, definitely get this game!