If anything, the most striking departure from the FF formula may be the dungeon layouts, not the battles (more on them later). Outdoor locations are huge, interconnected areas - deserts and plains, so far. Indoors, however, things feel much more grid-like. This is true classic dungeon crawling. Though the exploration is on the rigid and mazy side, Vaan moves quickly, and thanks to a helpful map, you can't get lost. Many dungeons are broken up by tasks like killing certain electricity-gobbling monsters, or collecting energy from giant glowing stones.
But more about those battles - as explained before, FFXII drops the series' traditional random battles and throws you directly into conflict as you explore. Enemies roam freely and if you get too close, you'll be forced to fight. You control the main character; though you can issue direct orders, the rest of your party typically behaves according to a set of rules known as Gambits.
For example, you can set the rule "perform this action when someone falls below 70% hit points" and the action is "cast Cure." Another example might be "target the enemy in front of you" and the action is "attack." You can mix and match rules and actions - of which there are only a few at the outset of the game, but dozens and dozens of blank spots for more (which you can find in treasure chests or buy at the Gambit shop). You can also open up more slots for new Gambits as you futz around with the License Board, the system which allows characters to learn abilities.