I’ve been trying this updated 5.4.20 kernel out, and for mupen at least, I’m seeing slightly better performance. In particular, trying out banjo Kazooie, Mariokart 64, Mario 64 and Zelda OOT. Less micro stutters and graphical artefacts mainly. Slightly smoother.
Retroarch seems less prone to randomly quitting on load, but that could just be luck.
I haven’t read all of the commits in github, and perhaps things weren’t changed that much. It could be a placebo effect. But either way, it’s seemingly improving performance. Looks like a lot of GPIO changes, and port activation. And of course general updating of the kernel files. I may need to update to buster properly to make use of all of the optimisations. I’ll look into that, and find a way to not have everything break as it usually does. I think there was talk of doing this in another thread.
I’m not sure who asypost is in the forums, but I did notice that @shell has made commits to it, and @guu is following. If either of you know who they are, let me know! I’m thinking about including it with the next release. This one seems like a keeper!
If you’re out there asypost, I’m loving your work! 
In other news, looking into other threads, I’m considering including the DS emulator mentioned earlier in the week. Would that be something people would like to see?
Adding a streamlined way to include the Godot assets and marketplace would be an interesting direction for the gameshell. I’m looking into it with a keen eye.
It’s been fairly quiet lately, gameshell progress wise, so nothing much else to add or report on. Work has also picked up again, so that works out well.