Ganbare Goemon Gaiden 2
|Ganbare Goemon Gaiden 2: Tenka no Zaihou|
This game has hidden development-related text.
Ganbare Goemon Gaiden 2 is an NES game by Konami that was only released in Japan.
At the end of the PRG ROM, an ID string lists the game version and date:
MSTR means it's the "master" version of the game, and the numbers are the date, so this version was compiled September 27, 1991.