Here are some cheats and tips for the game Famicom Mini: Ghosts ‘N Goblins.
Level select:
Hold Right and press B(3). Release Right and press Up, B(3), Left, B(3),
Down, B(3), Start. A number and letter will be displayed. Press A or B
to select a new starting level and press Start to begin game play.
Bonus message:
Complete both quests, then press A, B, Up, Down, A, B, Left, Right.