Atmospheric effects (fog, fire, black smoke, water leaks, flashing lights)

Yeah not much to add here, RCT3 had this and RCT2 as well in which you could place elements that would add things like fire and smoke which were great for when a coaster would dip into the ground or just look cool for making a industrial or spooky surrounding.

The down side was that fog was pretty resource intensive on PC, placing a few would slow down weaker computers pretty fast.