It is pitch black. You are likely to be eaten by a grue.
So apparently Zork is 30 years old this year. Man, I loved those games. I played just about every Infocom text adventure on my little Atari 800xl home computer.
If you've never played it (or if you need a little nostalgia fix) you can play the original Zork here.
Also, on Barbelith a few years back, we had a fun thread where we simulated an Infocom text adventure.