Enemies reworked:
Rats - will surround you rather than ambush you. (Also other encounters, much more rarely)
Imp - become skirmishers and will use fireballs. And yes, they are still invisible until you get close...
Vampire gets new skills and unique spells. You will have access to them if you manage to hire her - (they are added at hire time, so sadly not if you have already hired her)

New Weapons:
Flails (Hard to use, but enemy shields useless)
Hammer (Can be used to destroy enemy armour)
Scythe (Only one attack mode, which covers 6 squares!)
Pike (Reach 3 & repel enemy)
Halberd (Reach 2 & hook enemy closer)

New weapon abilities:
2 Handed Sword - Overhead chop - area affect, 2 squares forward.
2 Handed Axe - The Haymaker - All or nothing attack - lots of damage, leaves you vulnerable next turn.
Sword - Counter attack - if the enemy attacks and misses, you get a free attack back.

Rework of how ranged chances are shown to user:
You now get a percentage chance shown by the cursor, plus a list of all the factors that are affecting the shot chances.
Any terrain or characters in the way will be highlighted in red.
Any terrain or characters close to the expected flight path will be highlighted in yellow.

Added 50% chance of inaccurate missiles not hitting anything at all, even if it deviates onto another occupied square.
It was virtually impossible to miss if you aimed at a large body of troops.
Many changes and fixes to balance missile fire.

Review of enemies speed on the strategic map - assuming you are not lumbering about in plate mail/with injuries/with vast amounts of heavy trade goods, there should be very little that is faster than you now.
Also, far fewer things should flee you on the strategic map.

Bugfix - sometimes summoned units entered the battlefield invisible and the battle became unwinnable - fixed!

Bugfix - Music and sound volumes can now be updated without needing to restart the game.

Bugfix - If you are on a caravan mission to a place that is destroyed, the mission is now immediately cancelled and you regain control of movement.

Bugfix - Expanded skill descriptions in combat featured control characters - removed.

Bugfix - Bizarre bug when you had help (e.g. militia) and no adventurer in slot #1.

Bugfix - Account for all help when giving out experience points.

Bugfix - Solo achievement will no longer fire with militia help.

Keyboard shortcut added - Ctrl G - Toggle Grid on and off in combat.

Keyboard shortcut added - Ctrl T - Toggle Fade trees on and off in combat.

Rework display of Hit Points - can now more easily see the actual number of HP remaining. (Mana also)

Movement Grid now has a darker border to make it a bit easier to see.
(You can turn the opacity of this up or down also in Options screen)

Skills re-coloured:
Orange - characteristic upgrades
Yellow - skills that have to be used in combat
Passive skills stay white
Spells stay blue

You can now pan the map whilst holding middle mouse button

New option added to disable screen edge scrolling

AP shown when moving is now AP left rather than AP cost

Tooltips added to party faces in lower left

Warning added if you create a party with a name that already exists (party name is used as save game name)

Difficulty tweaked up, slightly...