So I finally made it to the end of the game (on Normal, now I can go back to Classic).

Why the heck is the last level so friggin dark?? The Ethereals ain't paying their electricity bills?

I have to question the level design of fighting through every type of ET in the game, though. There really isn't any challenge to Sectoids, Thin Men, or regular Floaters and Mutons, or even Chryssalids and Cyberdiscs by that point. I get that it was for the BBEG to explain all the different aliens to us, but I really expected a greater challenge.