This level is more-or-less linear and isn’t an overwhelming challenge, but will task you to escape an abandoned missile silo that the spiders have converted into their lair. Basically, there’s only one real path to follow and it will lead you from area to area where you’ll need to turn on lights, lamps and lanterns to keep the spiders at bay. Whenever you come to a room with a light in it, be sure to scavenge thoroughly, especially for Shotgun shells and Flame Thrower fuel which can be found in white plastic jugs and gas cans. Spiders can be dispatched in the same way as the main game, hold your headlamp on them until they flip over and then either shotgun or knife them by pressing . Be sure to keep your headlamp charged up as well!
The most difficult portion comes at the end when you have to wait for an elevator to arrive for escape. You will be beset by spiders the whole time, so be sure to have plenty of ammo/fuel left for the ending sequence. You will recognize you are getting close to the end when you begin climbing the floors around the missile itself. Enter the elevator to end the level and unlock the achievement.