Has anyone tried The Forest? Currently exclusive to PC; a PS4 version is in development.
An ever-expanding open-world forest island is populated by smart and cunning, but primitive cannibalistic natives (plus tons of woodland critters and living, lifelike flora). By the light and safety of sunlight, you're tasked with organizing and establishing a means to survive the nocturnal native activity.
I'm blown away by the AI so far. The cannibals are believably cautious; they don't charge you relentlessly like every other survival-horror enemy. They hang back, communicate and coordinate with fellow tribals, and monitor and adapt to the player's behavior. Fallen trees, remains of campfires, etc. will provoke the cannibals' curiosity, causing them to investigate the player more closely, etc.
It's very easy to sink lengths of time into this. This is the most engaging and captivating game I've played in a while. Hope there are a few players here, I'm dying to try co-op.