XIII's 'Stagger' system works like an armour break, allowing you to do extra damage and launch enemies high into the air.
Conversely, however, some mechanics have evolved for the better, and FFXIII's Active Time Battle (ATB) combat system is one of them. FFXIII's combat is like the lovechild of FFXII's divisive Gambit system and FFVII's classic ATB system. Like in FFXII, all three of your front line party members are visible as you explore the game world, and you can avoid many of the enemies you see pottering about waiting to be disturbed. But unlike in FFXII, when combat is triggered there's a short transition to a battle screen, where all the action kicks off.
FFXIII's ATB gauge charges continuously over time. Commands cue up, each one with an associated ATB cost. At the beginning of the game, each character's ATB Gauge only has a couple of segments, limiting the number of commands that can be cued up, but as you progress you gain more - up to a maximum of six. Once the ATB gauge is filled, all the commands play out one after the other in real time. When you've got a three person party going up against multiple enemies using spells, melee attacks, and other abilities, combat is a spectacular, visceral sight.
Now, you may wish to sit down for what's coming next: you only ever control one character during combat. We know, madness, huh? What has Square Enix done? Why have you dumbed down FF for the casual noobs! Calm down, dear. It's actually really good. Yes, you only control one character at once, but, with the Paradigm Shift function, you indirectly control everyone, and the AI is really, really good. Say, for example, you're controlling the gunsword-wielding Lightning, with the broad-shouldered Snow, and the moody Hope backing you up, and with the Strategic Warfare Paradigm (Commando, Sentinel and Synergist) enabled. As Lightning, you'll be concentrating on doing damage to your enemy with melee attacks - dealing physical damage to multiple targets with Blitz, perhaps, or maybe just slashing the crap out of a single target with basic attacks. While you're busy getting your game on, the AI makes sure Snow and Hope are doing their bit as effectively and efficiently as possible: Snow attracting the attacks of enemies with tanking abilities like Challenge, and Hope buffing Lightning and Snow and himself with spells like Shell and Protect.
Of course, the AI doesn't always do exactly what you want it to, but on the whole it's pretty smart. For example, if you use Libra to learn an enemy's weaknesses, your party members will automatically exploit them by using the appropriate elemental attacks. We only ever found the AI wanting when controlling Medics. When a party member is knocked out, an AI controlled Medic always prioritises raising everyone's hit points over reviving the downed character.
FFXIII's combat system is the best the series has seen. It's exciting to watch, fun to use, and, most importantly, brimming with strategy and depth. The only problem with it - and this will be a big problem for some - is the Auto Battle option. Here, with one button press, you can let the computer decide which commands to cue up for you. It does such a good job that it's all too easy to sit back and spam Auto Battle without mentally engaging in combat. The game doesn't do itself any favours by being ridiculously easy for huge chunks of its first 30 hours, only spiking the difficulty for bosses and "Eidolon" fights - FFXIII's disappointing transforming mechanised monsters must first be "tamed" before they can be summoned in battle. It's perfectly possible, then, to play for hours on end by only pushing up on the left analogue stick when exploring and pressing A/X over and over again when in combat.
Story is, of course, massively important for Final Fantasy fans. The great news is that in this regard you won't be disappointed. The game begins with a sabotaged train journey in which members of a resistance force battle against an oppressive government and what's called The Purge - an effort to deport citizens of a spherical world called Cocoon to the underworld below. It's all to do with horrible beings called fal'Cie, which turn ordinary people into slaves called l'Cie. L'Cie are given what's called a Focus - an order, essentially, which they must carry out or face being turned into mindless zombies. Either way, though, l'Cie are screwed. Complete a Focus, and they turn into crystal for the rest of eternity. This is the terrifying fate that Lightning and the rest of FFXIII's eclectic bunch of adventurers face when, early on, they are cursed as l'Cie. The game revolves around their attempt to work out what their Focus is, while unravelling the truth behind the oppressive government Purge.
FFXIII starts slowly - very slowly - but it hits its stride around the 20 hour mark, evolving into an entertaining romp packed full of drama, revelation, and more drama. The six main characters are annoying at first, but they all grow as people as their lives spiral inexorably out of control. Hope, for example, starts off as a spiky-haired whine-bag hell-bent on stabbing Snow in the back for murdering his mother. 'Oh god', you think, 'not another JRPG emo!'. But as you play you can see Hope growing up. In their own ways, all of the central characters do this. It's sophisticated, engaging, and helps drive you to finish the game despite its faults.