슈퍼 마리오 랜드

Expert mode:
Successfully complete the game one time, then press any button at the title screen. The pointer will turn into Mario's face to confirm correct code entry. Press Start to begin game play with a higher difficulty level.

Easy mode:
Press Select at the file selection screen. Mario will shrink to confirm correct code entry. Select a file to play the game in easy mode.

Level select:
Successfully complete the game twice in succession. Press A to change the starting level number which appears next to the final score. Press Start to begin at the selected level.

Continue game play:
Hold A at the game over screen. While keeping that button held, press Start when the title screen appears.

Three lives:

Press A just as Mario enters the Bonus room. He will be lined up with a ladder that leads to three lives.

출처 : http://www.gamewinners.com/game_boy/SuperMarioLand.htm