Games : What changes during the night-time?

I loaded up Pixel Dungeon at 12:31 AM today, and was surprised by the orange text "Be cautious, since the dungeon is even more dangerous at night!" That got me wondering. What all changes when the dungeon enters its "night-time" mode?

NOTE: I do not know if this applies to the original game, as I am playing an upgraded version called Shattered Pixel Dungeon.