Arizona Sunshine is releasing a new map today for its horde mode. In horde mode, you and up to three other players must work together in order to fend off waves of the undead while managing limited ammunition and health restoring items. Since launch, Arizona Sunshine has had only one horde map that is set in a brightly lit outdoor encampment. Today’s update however will take players where they hoped they’d never have to go again: back into the mine.

The mine is a level in Arizona Sunshine’s campaign mode that has become notorious for being the most horrifying 20-30 minutes of the entire game. The mine in the main game is pitch black with the only light source emanating from your flimsy flashlight or a few weak generators scattered around the map. Similarly, the new mine horde map surrounds you in darkness and makes you question what lies around every shadowy corner.

We had the chance to try the mine horde map at GDC 2017 and there a few things players need to be aware of before hopping in to this gut wrenching new experience. The first is that this map is significantly larger than Arizona’s original horde arena. That map was essentially a square that you could cover in a few seconds. The mine, however, is so large that you’ll have to actually hunt down zombies to progress through early waves rather than just letting them all come to you in a funnel.

According to the Vertigo reps at the GDC demo, exploration will be essential to succeed in this new map. Ammo and health will not simply spawn at your relatively well-illuminated starting platform. Instead, you’ll need to grit your teeth and march into the dark unknown if you really want to go for the gold.

I played this map with unlimited ammo and invulnerability at GDC and I was still terrified out of my mind. My advice to you is to bring a friend, or two, or three. These jet-black caves are far too terrifying to challenge solo.

This new map will be filling in for the promised Las Vegas DLC that was slated to release last month. According to Vertigo, that content is now being slated for late March instead.