It's an active time battle system that's been reworked to make it run as fast as possible. In fact, a lot of your reward after the battle is based on the time it takes you to complete it. You only have control over the party leader, but the other two support you based on a predefined role you choose for them. The main character's ATB gauge is divided into segments, with each segment representing an action. You can then choose to fill each segment with an action (more advanced actions take multiple segments), and when it's fully charged, the actions are carried out. Or, you can press the triangle button (probably Y on 360) to end your turn and only carry out the actions that the bar charged to, which is helpful if you just want to get a quick attack off, or if you want to end your turn quick so you can use an item. They also add on more depth as you go, allowing you to chain combos against enemies in an effort to knock them off balance to weaken them.