There are many Retropie based handheld game consoles out there, but few are designed to be easily built. The Muon was designed for the computer engineering club I run as a project to teach PCB and circuit design. Many students had never soldered before, so I relied heavily on through hole and large surface mount components. Additionally, it features a larger display than most Retropie handhelds, and the Pi 3 gives it enough horsepower to emulate most retro consoles!