Is it a guitar that’s also a Game Boy, or a Game Boy that’s also a guitar? We just don’t know.
This is a thing of beauty. Best of all, for me, is the way the A and B buttons don’t just control the Game Boy; they’re also volume and tone dials.
The build uses the guts of a real guitar. Fibbef, the maker, who created the Guitar Boy for the BitFix Gaming 2015 Game Boy Classic build-off, built his own guitar body with a screen and rammed a Raspberry Pi running the RetroPie games emulator in there, ending up with a functional guitar that’s also a functional (giant) hand-held gaming device.
If you want to see more of the build, Fibbef documented it in this thread at the BitFix forums.