Spelunker 2: Yuusha he no Chousen

Spelunker 2: Yuusha he no Chousen
Developer: Now Production Publisher: Irem Platform: NES Released in JP: September 18, 1987 This game has hidden development-related text. This game has a hidden level select.

Spelunker 2: Yuusha he no Chousen is a title only released in Japan that has nothing to do with the original Spelunker or the Arcade game also named Spelunker 2. Instead, it's a somewhat more open-ended platformer game akin where the player can either take the treasures for themselves or save Fairy Land.

Debug Mode

The Game Genie code NNNYEYAE re-enables a debug mode. At the title screen, press Start once, when the program is waiting for a second press of Start, use Left and Right to increase the location number by $10 and $01 accordingly, and press B to increase the world number. Start a new game as usual to begin with the selected world and room. Other features seem to have been programmed, but they have been removed from the game completely.

Hidden Text

Several RAM pages start with text strings describing their content:

0x008010 : "BANK=2 (CHIJO)" (above ground)
0x00C010 : "BANK=3 (CHIKA)" (underground)
0x010010 : "BANK=4 (ISEKI)" (ruins)
0x014010 : "BANK=5 (ENDING)" 

(Source: Cah4e3)