Gradius

Full Option Command:
In the Wii Virtual Console version, press Start during game play, then press Up, Up, Down, Down, Left, Right, Left, Right, B, A, Start.

Continue:
In the Wii Virtual Console version, press Down, Up, B, A, B, A, B, A, Start at the "Game Over" screen. This code can only be enabled once per game.

Full power-up:
Pause game play and press Up(2), Down(2), Left, Right, Left, Right, B, A, Start for missiles, items, and shields. Note: This may only be done once per level.

Continue game play:

Quickly press Down, Up, B, A, B, A, B, A, B, A after losing the last ship on level two or higher.

출처 : http://www.gamewinners.com/nes/Gradius.htm