Couldn't they make a virtually destructable environment using something like the Frostbite engine?? It might be possible with damage being restricted to a predefined "grid" throughout the level, meaning it melts things in controlled hunks wherever it lands. The melting could never go through the bottom "floor" of the level, the sub-Newt-kidnapper-basement with the sewer water or whatever the nasty crap was. Why was that under the walkway floor, anyway? And weren't they on the second floor, since that's where Operations was and they took the elevator down?
Does that mean that there was some sort of wastewater river level in between levels 1 and 2?
Anyone remember the first Red Faction? You could blow holes through the levels because you were in a mine and had, sort of, seismic survey charges. It was totally awesome, PS2.
Of relevence - http://en.wikipedia.org/wiki/Destructible_environment
I would enjoy a Realism mode like Left 4 Dead, but with full acid damage and sadistic alien horror ghosting your motion tracker and hiding in the dark waiting for you to walk by so it can grab you with razor-steel hands slick with slimy fear. And if you were kept alive, you had to watch your character be dragged screaming back to the hive, stuck to the wall, forcefully impregnated through the face, then eaten alive until the newborn xenomorph erupted violently through your sternum. The controller should vibrate, or something.
And please make the pulse rifle really f**king loud