@moosepr designed this small and simple GameBoy-style device using the Raspberry Pi Zero:

GameBoy Zero, but smaller!

I’m not overly fond of ‘rats nest’ wires, and I have a bit of an obsession with making things as small as possible, so this is what I came up with.

Tis just an ILI9341 screen, a Pi Zero, 2 navi switches (5 way), and a battery (with charge/protect circuit)

petay has shared the board on OSH Park:

Here the board is in action: