It seems like since I first tried the game, it's gotten really slow on my machine, which is very odd, considering that it's a desktop ryzen 9 with 16 cores and a beefy graphics card. Weirdly, it still runs fast (and is consequently much more difficult) on my laptop.
Just tried it on my son's machine, which is the same hardware as mine (but running Windows rather than Linux, both of us using Brave for browsing) and it's fast there too. On my machine, even the clock rendering is dramatically slower than real-time; I'm not sure what's going on.