The beginning of the last trip to the Pfhor ship, and boy, it's a doozy. Hunters and Wasps are the only enemies on the level, coming at you from every angle. The level opens with an ambush, a group of Wasps flying out at you from a room which is also rigged with a 5-Hunter booby trap. The way to defeat this is fairly well-known: "Reach" across the trigger and open the 4 doors seperately, dealing with the hunters one at a time. The fifth door is too far to reach without stepping on the trigger, but by then the room will be empty.
The next challenge is a short drop into a tight set of passageways stuffed with monsters. The cheap, if safe, way to handle this is by jumping down, waking everyone up, and hopping back on the platform before they reach you. Then they can only come at you one at a time, riding the lift.
The next stop is a huge silver room with a column of green slime running down the center. This room can be defeated fairly easily by exploiting a bug in Marathon's physics. Pop open the door and fire off a few rounds, then slam it shut as everything wakes up. Wait a few seconds, then get as close as possible to the door (don't open it!) and fire up the Tozt. Apparently Pfhor doors are made of chicken wire ;P (This trick doesn't usually get them all though, so stay on your toes when you finally enter).
This room has two exits: One in the middle leads to a strangely vibrating corridor and a 3x health charger, and one which leads to the rest of the level. The rest of the level is a set of large rooms with columns of slime in them, and a number of Enforcers and Wasps to deal with. At the north end of the catacombs, in the room full of baby Hounds, is a pattern buffer, and near the entrance is a very, very useful teleporter that will return you to the 3x charger room.
This level also has a few of that rarest of rare, mapmaking mistakes by Bungie. Firstly, there's the "magic flamethrower" bug mentioned earlier. Secondly, in the passage just preceding that, the window behind a door is bouncy, one of the few places in Marathon 1 where that problem can be seen. Thirdly, in the 3x recharger room, one of the space polygons has the wrong height. Looking from the left, the Marathon appears to be sliced in half by the cosmos itself.
