STarted IT recently, what did it add onto TQ?

[JnEricsonx]

Aside from Dream, etc?

[Lanceor]

Dream, Act IV, Artifacts, Enchanters, transfer area in caravan, artifacts, many new items.

[ivo111]

Dream, Act IV, Artifacts, Enchanters, transfer area in caravan, artifacts, many new items.

Aside from that, many new relics/charms and MIs, scrolls, tombstones, new quests, enhanced toolset and the bugfix community patch only works if you have IT.

Furthermore:
-Level cap raised to 75
-Pet controllers (aggresive/normal/defensive/passive stances)
-Improved monster AI

New features:
-Lock item pickup (optional, check options to enable/disable)
-Undo attribute points
-Extra audio options
-Gamma slider
-Much more details etc.
-Right-click to equip/sell items
-3x buffering
-Display health/energy
-and more...

Check http://titanquest.wikia.com/wiki/Titan_Quest%3A_Immortal_Throne for all features.

So yeah, you're kinda screwed without it :D

[JnEricsonx]

Act 4 is Olympus, right? How did the game end originally in act 3?

[ASYLUM101]

Act 4 is Olympus, right?

No, Olympus is part of Act 3.