Make it of real strategic use
Hey there, I was thinking about the infested areas and something just sparked.
Instead of merely infesting the ceiling (or floors or walls), just adding a layer of organic looking stuff, why not give it a little structure? I was thinking of it being fairly thick in areas or something, make sort of a zig zag within the material... channels for skulks to run.
For example, the ceiling could do something like this (but certainly not so defined):
Think winding intestines or just organic growths making non-straight paths, not hard corners. It would be an interesting development... it would provide a lot of stealth ability by giving the aliens some kind of route, adds some protection because of the physical wall sides, and could make the dynamic infestation a real strategic boost for aliens (and a nightmare for marines) especially when in combat.
Maybe it needn't be tunnels or channels, maybe it could be just ceiling/floor being of different heights in the infested areas... providing some kind of bumpy surface in alien areas where the infested material can make marine movement more difficult and provide nooks and crannies for little skulks and gorgies to duck into. I wish I could better illustrate this concept. It would be like "growing" the infestation with heightmaps of an organic pattern in such a way so that the infestation comes in making it all bumpy but in a pattern that provides routes. Hmm, what do you guys think?