1. There's a clairvoyant bull called Bull. His best friend is another bull called Bill.
2. A key subplot revolves around the cross-social class romantic struggles of two cats.
3. An interdimensional massive threat to all lifekind as we know it is treated as a middling and not terribly pressing subplot for most of the game.
4. Blood conducts electricity, making for some interesting fights when your blood-splattered heroes start throwing lightning bolts around.
5. Early in the game you meet a talking clam which quotes from Moby Dick.
6. Zombie enemies occasionally sport the names of the person they used to be (like 'Rob'), to make you feel slightly bad when you splatter them.
7. You create two PCs instead of one, and can have them spend the whole game bickering with one another if you want to explore the duality of your own psyche. Or merely accelerate your own inevitable mental breakdown.
8. It has the best combat seen in an RPG since Baldur's Gate II.
9. It's basically the product of an unholy union between Baldur's Gate, Diablo, Ultima VII, XCOM and Myth (the pre-Halo Bungie strategy games). Simultaneously.
10. It'll more than adequately fill the time until Pillars of Eternity and Elite: Dangerous come out.
Divinity: Original Sin is available on PC now.