New Super Mario Bros./Unused Scenes
You can change the current scene by pausing the game, setting 0x203BD30-0x203BD31 (in the USA version) in the memory to 0xXX00, where XX is the scene ID in hex, and unpausing.
"WORLD" - Early World Select Menu (Actor 8)
["select a world."] When you stop at a world, the "player stopped walking" sound from the world map plays. ["debug menu."] For some reason, it loads the world map bottom screen pallete file and the single player level bottom screen pallete file.