Great - almost photographic. The thing that gives it away the most is the skeleton cos it has a dark halo around him and I bet that token came with that halo as part of it. Another thing might be to desaturate it a bit because eyes don't see color so well at night that everything turns monochrome. Its well moody tho and I bet if you had some low level skeletons they would give more creeps to players than if you had that map in daylight. Its not something I have considered in the past but I bet theres a subliminal effect that a GM can exploit.