Gradius II/Secrets

30 Lives
At the title screen, press.

Activate full power-ups
During the game, press to pause the game, and then enter. Then press again to unpause the game. This may be used once per level.

Sound Test
To access the sound test mode, press and hold while turning on the NES/Famicom. While holding these buttons down, press to access the title screen (if you're not there already), and press  as if to begin a new game. Then the sound test menu will appear.