It's not anything we couldn't figure out with the trailer, but it's worth a read anyways
http://www.1up.com/do/newsStory?cId=3173436
Final Fantasy XIII's Battle System Exposed
A preview of what you'll be seeing in a few weeks.
Regular non-gaming-industry Joes will have their first crack at Final Fantasy XIII in only three weeks, once Final Fantasy VII: Advent Children Complete hits stores in Japan. Kind of crept up on all of us, didn't it? The epic RPG, due out before the end of the year over there, looks to involve everything people love and hate about the series -- and if the battle system (first revealed in full this week in assorted Japanese magazines) is any indication, fans don't have much really new to worry about.
The battles in Final Fantasy XIII are basically realtime; you can see enemies on the game map and fall into battle when you come into contact with them. Your party has a time gauge that fills up over...time, and once it reaches a certain level, you can execute commands. This is sort of like the "Active Time Battle" system we saw up until Final Fantasy IX, but unlike before, commands can be executed even if the time gauge isn't completely full.
You see, the gauge is divided into sections; when each one fills up, you are able to execute one command, such as "Fight" or using an item. When the gauge is full, you can input several commands in one go and watch as your party executes them all at once, with the results depending on the sequence of your orders.
Every command, meanwhile, has an associated cost. For example, while "Fight" only consumes one time unit, trickier magic could cost three or more units, draining your time gauge rapidly. While unconfirmed, it seems likely that more time units will be added to the gauge as you levels up, and that'll be important -- given that there's no visible MP display on the battle screen, there's a decent probability that magic works completely off the time gauge and there's no MP concept here at all.
Like in most recent FFs, chaining attacks plays a major role in the battle system. Attacking the enemy multiple times in rapid succession results in a Chain, which gives a bonus to the damage you deal. Linking a chain together fills up a gauge on the top right of the screen; once it reaches a certain level, enemies will start to flash red onscreen. Keep the chain going until you fill the gauge to maximum, and enemies will go into Break mode, letting you deal even more damage until the gauge is fully exhausted. Enemies in Break mode can be thrown into the air with a dedicated command, letting you juggle them around for -- you guessed it -- more damage. (You can't juggle really huge monsters, of course, but there might be some other method of making them vulnerable for a short period of time.)
There's no doubt more to the battle system, of course, but further details will have to wait for the launch of FFXIII's demo, due April 16 in Japan.
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Overall, I'm very interested in the battle system of the game, it has a certain Xenosaga vibe that attracts me, and FF's battle systems have almost always been good, so I doubt this one will disappoint
