The game is shaky on it, particularly with respect to floors and ceilings. If you use an area-effect attack in a cave, everything on tunnels above and below you might come running for you. That is if you are lucky: they also might start hitting you through the ceiling. This is a fun way to discover when a building has a basement or a hill has a cave: attack enemies on the surface and see if invisible monsters start eating your ankles.
Did I mention that I have an AE-specialized character? Good times.