The original Dissidia met a mixed response from fans due to its rather unique combat system. Instead of copying the model of other fighters -- Nintendo's Smash Bros., or Capcom's Vs. series -- Square Enix crafted a battle system inspired by Advent Children, but still rooted in RPG mechanics. If that doesn't make much sense to you, you are not alone.
Arguably the biggest new feature for Duodecim is the addition of an "RPG Mode" that strips down the combat experience into something that might be a bit more familiar to traditional Final Fantasy players. Unlike the traditional "Action Mode," you lose direct control over your character in this mode, relegated to selecting commands. You'll be able to switch between attacking Bravery and HP, or choosing a more defensive role. It may seem like the game is simply controlling itself, and to a certain degree, it is. However, this mode lets you understand the various mechanics that are at play in Dissidia without being overwhelmed.
If you've already mastered the nuances of Dissidia's combat system, you'll probably skip this new feature. Instead, there are new mechanics to master. You now can assign an Assist character, and as in Marvel vs. Capcom and Naruto Ultimate Ninja, you'll be able to summon an ally with a quick button press. Depending on your Assist, you'll be able to stop a fleeing opponent, deal more damage, or lengthen your combo. The Assist also provides the valuable fan service of hypothetically making Cloud and Sephiroth partners -- you can already hear the fangirls squealing.
The new characters also offer their own unique abilities. Lightning, for example, is able to use Paradigm Shift on herself to change her battle style on the fly. It'll be interesting to see how other additions to the roster will change the experience. There's also multiple difficulty settings, which should appease both newcomers and hardcore veterans alike.
I wasn't expecting much more than an expanded roster out of Dissidia's sequel, so I'm glad to see Square Enix make some rather significant enhancements to the experience. Final Fantasy fans that dismissed the first game will definitely want to give its sequel a second look. Duodecim will be available in Japan in 2011.