Chopper preview
Highlight a chopper on the chopper selection screen. Press (L) to display the statistics screen. Press the Analog-stick to control the rotating model of the chopper.

Alien weapon
Complete level 7 under the expert difficulty level. Then, fight on the moon to purchase the alien homing plasma weapon.

King 10
Locate King 10 in level 7, defeat him, then complete the mission.

Stingray
Locate Stingray in level 7, defeat him, then complete the mission.

Level select
Press (C-Up)x7 when "Press Start" appears on the opening screen.

Debug mode
Hold (Z) and press [Right],[Left], [Up], [Down], (A), (B), (Start) when "Press Start" appears on the opening screen.

Shoot down the President
Press (Z) + (C-Up) + (C-Down) during game play, then fire a homing cluster at an enemy plane.

Power chopper
Hold (L) + (R) + (Z) and press (Start) at the main menu before selecting a chopper.