Lots of balance tweeks and a few new features:
Injuries expanded and re-worked
You can now see how far your party can move
Fires burn out more quickly, especially underground
More descriptions added to the events, so you can understand the choice consequences better
Animation for ethereal
AI improvement for fly high (which is now allowed underground)
AI improvements for using several skills
"Chop" skill for monsters fixed
"Zombie Knife" artefact toned down dramatically (now raises 3 zombies max per battle)
New sound effects for some monsters
Elites generally a little easier