Why is it Raining in Here?

Seriously, what's with the rain, inside a video game, that takes place indoors. The dream would have been quite interesting if it could have continued, but my brain just wouldn't go along with the whole "it's raining inside" thing. The only bits of the dream I really remember other than the dark blues and blacks of the walls and the reddish brown color of the floor tiles is the stupid interior rain. Interesting lighting, too, coming as it was from the eastern windows set in long rows of slender tall paned windows with a pointed arch at the top. I can't remember the name of the shape now, but imagine the inside area of a wish-bone. None of the windows had curtains, but there was a thick layer of dirt and cobwebs that almost made it seem like there were curtains.

Despite the rain, the floors didn't look wet. That was a puzzler, too. I have no idea what the plot, theme, or genre of the game even was, though I am sure I knew it in the dream.