Pros:

Atmosphere
Plenty of weapons
Creative weapon locations

Cons:

Glitches

I know it is supposed to be dark, but the lighting was so bad I sometimes had trouble navigating the house.

I, for the life of me, could NOT figure out how to start the horde. Are you supposed to be able to? 
 

Conclusion:

If you can figure out how to start the horde, you could get some enjoyment out of the map. However, I was completely unable to. The map gives you no pointers on where to find it.