When I saw this project https://www.tinyjoypad.com/tinyjoypad_attiny85 I immediately want to create my own version of it to play the extremely excellent port of space invaders here: https://github.com/Lorandil/Tiny-invaders-v4.2.

Please note that this project isn't directly compatible with the tinyjoypad, but in my opinion the Analog control make all the difference to play this addictive Space invader port.
Most of the components are thru hole to be easer to solder except for 3, but still doable if you are somewhat skilled with soldering.

Although, it can be used with a single CR2032, it isn't enough in most cases to power the screen regulator, I recommend using rechargeable 3.7v LIR 2032, but you can use any li-ion battery you can fit inside, please note that the charger controller is set to charge at 100mHa.

For the cartridge PCB 0.6mm thickness is recommended, 0.8mm may also work.

Full case for console and cartridge included in STL format.
Enjoy!!!