Zanac

Level select:
Reset the NES system thirteen times, then press Select. Choose the "Continue" option and press Left or Right to select a starting level. Press Start to begin game play.

Sound test:
Hold A + B and power on the NES system. Alternatively, hold Start + Select + A + B at the game over screen. Release all buttons when the screen turns black.

Continue game play:
After losing the game on level 11 or 12, highlight the "Continue" option on the title screen, press Down, Up on controller two, then press Start on controller one. Alternatively, after the title screen re-appears hold Up + A + B + Select until "Continue" is highlighted, then press Start.

Ship power-up:
Hold A + B and press Start at the title screen. After six "6" power-ups are collected, all objects will transform into extra lives.

Transform ship:
Hold A + B + Select + Start when game play begins.

Hidden message:
Wait until the fairy stops moving during the ending sequence. Then, press A + B on controllers one and two.