The PowKiddy V90 is an awesome little Linux-powered handheld gaming device. It's reminiscent of a Game Boy Advance SP, and it is capable of emulating most GBA games, in addition to many other consoles including NES, SNES, Genesis, and even some PS1 games!
I love mine, but it's not without it's flaws. The Miyoo custom firmware fixes many of it's issues, but it's inability to charge from a standard USB Type-C ports is a hardware bug. So, it's time to break out the multimeter, soldering iron, and USB-C specification!