ARK is available now. It was released in June 2015. Steam, Playstation 4, and Xbox One have it as early access. Engine 4 was used in the development of the game which to the co-founder, Jesse Rapczak, was a must since virtual reality was most envisioned since the firsts ideas of ARK were proposed.
Among the most popular games to play on Steam, ARK is one of them, with over 100k players who have rated it as a fan favorite. To know more about ARK and to start playing this amazing game; Please check out: ARK: Survival Evolved