There's a strange effect that happens sometimes with darkness, particularly in cavernous areas. Occasionally, you will see a few squares on the board that don't appear properly filled in by the darkness. When you walk on them, it will say "It is dark here", but the tiles look like a regular square, and, from my understanding, behave as a regular square (eg. if a monster is standing on one of those squares, they will behave as though they are not in darkness).
This also happens in some rooms in the place where the door should be. Here's some screenshots that illustrate what I mean:
Code:
######### ######
# # #
# ############################### # ### ###########
# / / # # / # # #
########################### ##### # ####### # # #
# # # # # # # #
########### # # ####### #####/####### #
# # / # # # # / #
# # # # ####### # # #############
# # # # # # # #
# # ################### ############### # ##### #
# . # # / / # # #
############# # ######### ################# ### # #######
# # # # # # # . #
# ### # ######### ### #
# / # # #
############# #######
The room in the lower left corner is under darkness (most of the level is), but there's one square in the entryway that is not.
Code:
###### #########
# ## #### ## #####
##### ## # # #### ###
##### ##### ############# ########## ## #
### #### . . ## ##
#### ## ########## ########### ## #
# ## # # # # . . #
# # # # # # #### #
# . . # # ## # ## # ##
######## . ### ## ## # #.#### #### #
### ##### ## # # # ## # ## ## ##
# ### ###### ############# ########## ## ## #
# . # # #
# # ########################### ############ #########
# # . #
# ############################# ############# ##
# # # ## # #
# #### # # ### ###
### ### # # #####
This cavernous level is completely immersed in darkness, but you can see that there are a couple of random squares that seem to be, for whatever reason, not in the dark.
[edit]I can post the savegame if that would be helpful. These are adjacent levels.