Zero Gunner 2

Full pause screen:
Pause game play, then press X + Y.
Information in this section was contributed by heoweir.

In-game reset:
Pause game play, then hold A + B + X +Y and press Start.
Information in this section was contributed by heoweir.

Expert mode:
Successfully complete the game under the arcade or higher difficulty setting to play more difficult levels.

Replay mode:
Successfully complete the game to unlock the "Replay" option at the main menu. Select it to watch the game auto-play.
Information in this section was contributed by heoweir.

Unlimited credits:
The game increases the number of available credits each time that it is restarted. If played enough times, your available credits will be unlimited.
Information in this section was contributed by jinyuan2401.

Hint: New shooting weapons:
Collect all the objects you see after the planes explode.
Information in this section was contributed by Andrew Kannadan.