The Nintendo Gameboy Color emulator, GNGB, is a nice program but comes with no graphical setup tool, so I simply just made my own. You can either run this by itself or open it with a .gb or .gbc file.
The only known issue is gngb-gui doesn’t like to open files with spaces included in the names. All other problems are probably due to the emulator itself.
Depends on: gngb, zenity