- If a COMBO is continued, a score will go up by bounds.

- When continuing a COMBO, make the most of a 'orange beam'. 
(an enemy plane is destroyed continuously)

- The enemy plane under descent is attacked as much as possible.

(Since the score of an enemy plane is high, a COMBO bonus

becomes large)

- The hit judging area of my plane is small  (about a central yellow

      portion), so you can go through a narrow interval.