For those that don't know, the demo for FF13-2 is available for download:
http://marketplace.xbox.com/en-US/Product/FINAL-FANTASY-XIII-2-Demo/66acd000-77fe-1000-9115-d80253518810?cid=SLink
It's a nicely long demo too, does a good job showing the minor updates they made to XIII's combat & Paradigm systems. Also, you can "tune" specific Paradigm formations to focus on multiple enemies / area-of-effect abilities, single enemy, or mixed/normal.
You now have 2 party members and the 3rd slot is occupied by a monster you have fought & tamed before. Different monsters have different abilities so the Paradigms are even more dynamic now. Battles are generated 'randomly' on the field like past FF games, and there is a "mog clock" feature that puts you in control of whether you get a pre-emptive strike or not.
The game seems to focus on Serah, Lightning's sister, as the main protagonist. She is joined by this new guy named Noel who is a bit less petulant and annoying than Hope. Supposedly, Fang, Vanille and Snow will also show up in the game but as cameos and not party members.
So far XIII-2 has been getting great reviews with most calling the story the weakest part. Due to the many complaints of the overly-linear nature of XIII and how it took 30 hours to get to the "world map", XIII-2 opens up much sooner.
The game is set to release Tuesday, January 31 here in the US.