Does the speedrun clock tick slower than usual (without using the assist mode to slow down the game of course)?
I just ran into this issue myself on my PC. On my laptop I played the game just fine but on my desktop everything seemed to be slower, noticeable the speedrun clock is not in time.
I tried to reinstall the game (both from itch directly and from the itch app), reinstall XNA as well. Running Win 7 on the Deskto, Win 10 on the Laptop.
I don't seem to have any issue with the CPU usage though, all cores down to a few percent (i7-6700K) but according to the windows resource manager thing the process has 28 threads opened, not quite sure if that's intended or just displayed incorrectly . There's plenty of available RAM. So I'm not sure if these issues are somehow connected to each other .
If there's any information you need from my sytem let me know