Jeff Geerling shared the video on Youtube and the Raspberry pi blog has a great write up!

Compute Module 4 is running RetroPie inside a salvaged Game Gear handset, giving the user access to as many classic games as the innards of their machine will allow. Jeff explains in his build video that he could have used a Raspberry Pi Zero 2 W or a 3A+, which would draw less power but wouldn’t be quite as fast.

Jeff found a used, broken Game Gear handset online, and turned to John Maddison’s Zega Mame Boy, a Game Gear modding kit designed for use with Raspberry Pi, to help with the transformation. A smaller, more powerful audio board stepped in to improve the Game Gear’s sound. He also got a new screen and some fresh buttons from Hand Held Legend to disguise the battle scars from hours and hours of use in the handset’s previous life. I know from personal experience that your screen will get scratched if you throw your Game Boy at the wall every time you fail to complete the Bowser’s Castle level in Super Mario Bros.