It's amazing what you can do with a few pixels, not only create a brooding night atmosphere but render shadows and weather effects in the dull illumination of the night lights. I think it also adds to it with the off-kilter composition.
This one is like a very old MS-DOS game or indie game featuring pixelated work all throughout, still managing to create a unique mood and atmosphere regardless. Truly amazing. :)
Link
Rooc
Simple yet beautiful.