This game has hidden developer credits.
Brother Adventure is an unlicensed port of Mario Bros., which uses music from Dig Dug for some reason.
It is known for being the first game to be developed entirely by Zemina, who would go on to create more unlicensed ports for the MSX, and later, the Sega Master System.
Offset 0x10 of the game's ROM data contains a build date and a set of programmer credits. Both of them are also credited in the title screen upon starting a game.
PROGRAMMED 1987/9/25 BY ZEMINA PROGRAMMER - KIM EUL SUK & KOO EUN JOONG
There is also a small annotation at offsets 0xD9B and 0x3769:
FROM THIS WRITTEN BY KOO EUN JOONG