yeah, it's pretty much about survival.
It’s the interactions with other players that make it more compelling than just exploring, avoiding zombies, and finding supplies. Some players will try to kill you for your supplies. Others want to join up and travel together (or join up to kill other players). You worry about killing zombies because your gunshots could attract players, and more zombies, or lighting a flare for similar reasons. There's a humanity system where killing players turns you into a bandit (there's a window where you can fight back once attacked without lowering your humanity). Saving other players by healing them and whatnot increases your humanity. Players can break bones, lose blood, starve, etc.
You start with a puny pistol, some food, water, and a few flares. You find can files tools like a compass to help guide you to other locations on the map, which you have to find too. You can find vehicles, including helicopters, and better weapons around the world. The main thing you do is survive. There's no real end goal, yet. This is still a really early mod. I'm not sure what the overall ambition is for it. It's really, really rough in its current state.