The video showcases upgrades to the battle system from XIII, and the ability to either chain together usual attacks, or hold off until more powerful ones become available. Square states that players will also be able to switch characters roles on the fly, switching your Ravager to a Medic with minimal effort. It looks a bit more complicated, but much more rewarding when things go off right.
There is also news regarding the story of Final Fantasy XIII-2. The story of the game takes place 3 years after the events of the FFXIII, and will feature Lightning's sister, Serah, as the main protagonist.
Final Fantasy XIII-2 is out in North America on January 31, 2012 on the PS3 and 360.