Gradius II: Gofer no Yabou/Secrets

Full power codes
For each system, it is possible to enter the "Konami code" or some variation of it to immediately activate a full power mode, which includes Missiles, four Options, and Shields. It is left to the player whether to activate Double or Lasers.

PC Engine: Arcade Mode
After pressing to load the game, press and hold  until the title screen is displayed. Then "AC.MODE" will be added to the Options menu. The only purpose this serves is be truer to the arcade experience by omitting the PC Engine exclusive stage.