The main impetus of The 3rd Birthday‘s battle system revolves around being able to morph into the bodies of other people – this is the Overdrive system. If one body is near death, just move yourself to another and go at it full force. But, on top of that, there are a couple other nifty game play mechanics that you can make use of – Liberation and Crossfire.
Liberation is activated by filling up a gauge (which you can do by killing enemies), and this basically allows Aya Brea to become a super-soldier – a stronger, more souped up version of herself. She can move faster, automatically dodge attacks (taking some of the strain of the player) and can fire special bullets. Crossfire is the ability to sync with another friendly character’s attack to fire one punishing barrage at the enemy. As you can see in the second video below, you need to wait for the gauge to fill up after initiating this fancy maneuver. Both the videos are below, showcasing these two techniques – the first is Liberation, the second Crossfire.