Back in 2021, [stacksmashing] found that it took little more than a Raspberry Pi Pico and some level-shifters to create a USB connection with the Game Boy’s link port. Add in the proper software, and suddenly you’ve got online multiplayer for the classic handheld. The hardware was cheap, the software open source, and a good time was had by all.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/05/13/this-tiny-game-boy-lets-the-real-thing-play-online/