Just try if this cap still works without the brocken leg.
The same happened to mine and the connector still works fine. Just without one leg on its side.

Try to insert your ribbon cable as usual with the right oriantation and insert the black cap.

Had the same issue. Look into the config settings for n64 emulator. Was it retroarch.cgf? I am not in front of my gameboy actually but somewhere in the emulator spezific settings file: just swap both axis inputs. -1,+1 to +1,-1 or something like that.

Nice build. My question is more about 3d printing:
But what happend to your printed cartidge? I assume the visible surface was not on the build plate!?
There are some waves inside the surface which I assume could been caused by not well tight axis belt.

Nice idea, I would assume to use one of this cases during a future build. Just some thoughts about: -Wifi and Bluetooth will be a problem inside a metal housing! -common ground by the case could been used but difficult to handle: each connection to the metal groud must be well sanded or grinded in o...

The behaviour of the running Pi itself let me guess it is not under voltage. For suddenly reboots I more feel its linked to a short cirquit from 5V power to ground.

Could be a lag of sufficent power. Or someting is shortening the power maybe from force to the case when you press buttons during games.

5 volts and ground you can find anywhere on the board. The data lines usually go to each a 22 Ohm smd resistor. Between usb jack and these resistors is where your usb data wires should go. Take care to measure the continuity after soldering data wires to this resistors since these components or thei...

Or more smaller caps in parallel to minimize hight.
As well for the integrated circuit if helpfull: To minimize hight you could use it without socket. Bent the IC pins by 90degrees to outside and solder them direct to the cupper side of your board.

I bought something like this:
https://www.ebay.com/itm/EVA-Hard-Carry ... nav=SEARCH
And if I remember right I cut and removed the inner seperator layer.

What you need is something like Pi UPS. Just google about it to get some ideas.