This new video of Final Fantasy XIII-2 shows how you can recruit monsters to your party. Once you catch a few, you can then assign them to slots in your party and use them in battle. I tried this feature out in a preview and found that it was pretty deep. You can really dive into strategy by assigning and switching up monsters for specific fights. Beyond this, you can even level them up and have them use other monsters' abilities.
Of course, you could go the whole game without messing with monster collecting. I found that it was pretty fun, and kind of reminded me of the Shin Megami Tensei games. I wonder if the SMT games inspired this addition.
While mostly unrelated to the monster aspect of the game, there is a nice collection of new Final Fantasy XIII-2 screenshots in our gallery below.