The Turn() Phase is a state that Red enters which stops the passage of time, enabling you to plan out moves to use up the action bar at the top of the screen. You will always be allowed to perform one last action regardless of cost to fill the action bar. Different Functions take up different amounts of the action bar. After planning out your moves, you can execute the plan very fast by pressing the space bar. Note that sometimes your plans won't turn out as depicted in the Turn() state, as some of The Process will move as Red is moving, causing you to miss an attack.
Turn Based Combat