During the opening sequence when the fighters are in flight, press Up, C-Down, Left, C-Right, Down, C-Up, Right, C-Left, L, R, Z. If you entered the code correctly, you will hear a sound.

When "Press Start" appears on the opening screen, press C-Left, C-Down, C-Right, C-Up, C-Left, C-Right, C-Down. Then, a hidden F-15 with a female pilot (Mao Mao) can now be accessed.

Compete all bonus missions to access Spanky as a hidden pilot.

A new enemy plane will become available in deathmatch mode for each level completed in the game. A total of six enemy planes may be enabled.

At the plane selection screen, press R, in main game practice or boss attack modes. For death match mode, hold R while selecting one of the four default planes.

Before reaching one credit remaining, reset the game and continue from the menu that immediately follows the title screen. Then the game will resume with the same number of credits that were available when the current stage was started.