Three extra continues: Press Down/Left + 1 at the "Game Over"
Continue game play: Press Up(2), Down(2), Left, Right,
Left, Right, Down, Up, Down,
Up at the "Game Over" screen to continue up to
Sound test: Press Right, Left, Down, Up
at the title screen.
Extra options: Enable the "Sound test" code. Play sounds
7, 4, 3, 7, 4, 8, and 1, pressing 1 after each sound. Options
to play the game as a jet, switch the vertical controls, and adjust
the difficulty level will be available.
View Haya-Oh: Hold Left at the title screen to view the game's
last Boss, Haya-Oh.
Secret message: Enter ERI as initials in all seven slots at
the high score screen.
Hint: Bonus points: Reach the round 5 bonus stage. Try to hit less than
three trees and weeds and do not try to get points. At the end
of the stage you will jump off the dragon and a plane will fly
across the screen. Shoot it down to get 10,000,000 points.