Ah, wrote the first response before watching the video.
Shame about the Windows version not working, and the stutters. It runs fine on my machines, but they are quite strong and I mostly test the native versions. Wasm32 by itself is probably already slower on the pathfinding code. What makes it even worse is that the web version has rendering and logic code on the same thread, and rendering in the browser takes about 10x as much CPU compared to native.
If you have the time, could you download HyperCoven and Sdlcoven and test if they run natively on your Windows version? - You will have to run hcv.exe directly, the launcher is the same in all cases. - It would help me decide which version to focus on. The FrontierCoven build is actually no longer using SDL at all, but some bleeding edge hipster libraries.