Apparently my UDP solution wasn’t working earlier (which I kind of noticed, but still not). I had refused to completely use recvfrom and sendto, which seemed to bind the sockets in a TCP-like fashion, and the UDP test was also not working as intended. Both of these seem to have been resolved now, and I think I noticed slight improvements with using UDP even on localhost (when spamming >100 updates per second, totalling to around 45kb/s in bandwidth).
Along with this I improved the UI system a bit more, so that I can now compile and insert complete UI interfaces or elements from other files wherever I want. So if you want to look at how many packets the UDP test has sent and received you can just press “U” in any game state and it will be pushed to the top of the UI stack (exit with ESC or right mouse button).
Beside that I have taken some time off, during which I’ve managed to create some new music to that game too. I’ll have to take a day or two to re-implement the Vorbis stream again which I left broken after Theora was added.