@chubsta If you are having problems, why not try finding those games on on other platforms? I also wanted to play Chuckie Egg, but I grew up playing it on a BBC Micro, and as yet Retropie doesn't support those, however there is an Atari ST version, which presumably would have better graphics than the Speccy one. Reading your post triggered that thought, and I found it today, and am hopefully going to find out how it works sometime this week.

@tredelijkheid In your custom Carbon theme in /opt/retropie/configs/all/emulationstation/themes, make a copy of the zxspectrum folder and rename it zx81.

I couldn't find any ZX81 artwork in the RetroPie themes but I did find a selection of ZX81 svgs in the Recalbox theme.

Download your preferred logo by right clicking on the image and selecting Save image as.... Save it on your PC as system.svg so it's consistent with the Carbon theme and place a copy in the zx81/art folder you just created and your theme is done.