Hidden images:
Insert the game disc into a PC compatible CD-ROM drive and look in the "Furoku " directory for several bitmap graphic image files.

Level select:
Successfully complete the game one time.

Select game speed:
Accumulate more than three hours of game play.

View attack range:
Accumulate more than twelve hours of game play.

Change plane speed:
Accumulate more than forty-eight hours of game play.

More credits:
An additional credit is available for each hour of game play that is accumulated.