Then 3 has the vote! The most combat-heavy route, for sure. I hope you guys can handle it!
But you are kicking off with a 2 by 2 route through the gloom; I shall use the revisions suggested to Peach's order. And so off we go...
Breathing is already difficult- the air is fetid and unpleasant. It's not just the lack of oxygen but the clear smell of corpses and other such matter.
Fights in here could be brisk and sudden. Please let me know what your starting schticks would be.
Then our first terrain feature you encounter is...
THE HIGH CORRIDOR
This is an elongated corridor that you can only move down two by two, but exceptionally high with the walls sloping up far above you. Obviously not a natural formation, this must have been shaped for the moving of relatively tall mining equipment. Some old lights flicker from above, giving this place a very strobe-lit feel as the light flickers into darkness and back continually.
It is as you are moving down here that you start to sense life nearby, and movement- and danger.