Game Title: Ninja Boy (U) aka Super Chinese Land (J)
View The Ending:
At the Title Screen press Up, Up, Down, Down, A, B, A, B, A, A, B, Start
First off I'm calling this Debug Mode instead of just Stage Select because you gain items also, and the Game Boy "Super Chinese Land" games contain the word debug.
Game GenieSuper Chinese Land (J)
Ninja Boy (U)
Enable the code and reboot the game.
On the Title Screen, after pressing start, you can use the directional arrows to change your starting level.
Once a stage starts you will notice you have more items in inventory than usual.
Normal stage 1:
Download the hacked roms to always have access without Game Genie codes:
Ninja Boy (U) (Stage Select).gb
Super Chinese Land (J) (Stage Select).gb