The only problem I see with this game is that there is no "endgame" per se. Your primary motivation when you start the game is to survive; i.e. collect food, find water and gather ammo. Once you've found things like a hatchet, a hunting knife and matches, food isn't much of a problem anymore. Adding more items to your gear (a nice gun, binoculars, etc.), you'll reach a point where you're beginning to wonder what's next.
You can easily avoid zombies if you know how to, so the only real threat in the game is its PvP aspect. Interaction with other players (as a bandit or a friendly) really is the only thing that's left once you've optimized your gear. I'm pretty sure a bunch of people out there are playing bandits because they don't know what else to do in the game. I've been running around as a medic, helping random people who are close to death by providing them with meat, painkillers and morphine, and hoping that they won't shoot me in the back in return (and so far I've been lucky!).
One "endgame" thing to do is to repair a vehicle. But once you've achieved that, you're back to square one, thinking: "Okay, now what?"
But make no mistake, you'll have many many hours worth of fun until you reach that point.