The sidebar now properly shows volume of sounds in or adjacent to the player's tile, as well as sounds made by a vehicle the player is operating. Previously it was failing to report a lot of sounds, despite that information being rather important.
This volume is based on heard volume, but capped at normal hearing level. This means if your footsteps are 6 volume and you have good hearing, they will still only show 6 rather than over-reporting. However if you have bad hearing, they might underreport and show 3.
Your footsteps now make their sound in the tile you're going to, not the tile you came from. This gives you more accurate reporting on the sound you're making and should prevent some weirdness where NPCs were sometimes frightened by their own footsteps.
Animated weather (rain, snow, fallout) wasn't being drawn in places like craters and ravines. This was because weather animations were only being drawn on z0. Now they are drawn on whatever z level the camera happens to be looking at.