: I guess if you view it like that what matters is on balance contrast; the
: Library and Midnight to me feel pretty oppressive with their samey
: Forerunner corridors, whereas Requiem has you go from wreckage to
: exteriors to interior Forerunner structures to outside again, with things
: like overgrowth spilling in from the ruins to break up the aesthetic a
: bit.

I'm drawing a mental blank on the names Midnight and Requiem (H4 or H5?), so I can't comment on your specifics. But at the very least, I think indoors and outdoors need to be considered as separate 'environments', as long as they're sizeable enough to be worth considering at all.

Hold on though, I've dug up a memory of Requiem after all. That's the one in H4 where you can drive down a long winding slope in a silly-sounding Warthog. I can remember that part of it at least. Only ever played H4 twice before my 360 bust. Never got back to it alas.