This level starts with a bang as four Hunters converge on your position, and doesn't let up. The Pfhor have one more trick up their sleeves: the Juggernauts. I was baffled and more than a little frightened by these things the first time I played the game. They are completely silent, except when they fire their seeking grenades or dual machine guns. They move very slowly and deliberately, floating over the decks or the lava. They appeared to be completely invulnerable to anything I threw at them, I could see and hear bullets bounce off their armored hides. It was a great victory when I finally managed to kill one.
This huge level is intricate, non-linear, and very well connected. There seem to be endless hallways to explore, and new discoveries to make all the time. It is possible to play the level several times and see totally different areas, or the same areas from many angles. The monsters are good at using the geometry to their advantage, they can follow you all around the map and come at you from unexpected angles. This level, in terms of design, at least, is very close to my ideal large Marathon map, there's just so much to explore.
With a level this big, one would expect it to be crammed with secrets, and boy is it ever. There are no less than three biobus chips available here. The first is an invisiblity behind the blue door in the room with the Juggernaut and the bridge; cross under the bridge's center to open the door and make your way back up. The second invisibility is in the Bungie Tip Terminal in the largest lava pool, grenade hop up to it or get the Juggernaut to blast you up. Finally, if you grenade hop onto the small blue pillar just beyond the 3x charger, you will be teleported to a small room somewhere in the lava canals containing a super shield. There are also assorted "normal" secrets: The gap between two lava pools contains some extra rockets (which you WILL need), and there are numerous piles of ammo scattered around the level. There is a 2x health charger placed at the end of a lava canal for no apparent reason. There's some intriguing level writing as well: A lava pool is labeled Fusion Vent #9, and the large room with the bridge is named Engineering Storage.