The main problem I was pointing at was missing oxygen-producing plants due to the extreme cold. But maybe life on earth isn't just a special thing and life on other planets is much more probable and not dependend on as many factors as we think.
Still, the "living underground" thing explains a lot. Guess the landing area is one of the few "above ground" places then. Actually I like the idea of a lot of stuff being build underground on such planet. Makes sense with the geothermal energy available.