It's probably because you forced VSync to OFF in your GPU settings. Turning it to ON or back to "Use the 3D application setting" should fix it.
I had implemented a safety measure to assume the game was running at 60 FPS in case the time elapsed between two frames was measured to zero (because web browsers can be very unreliable), but that safety can actually be triggered on the desktop version every other frame if the game runs uncapped at more than 1000 FPS (which is the case for me with VSync OFF). So the game believe it's running at 60 FPS when it's really rendering 1000 FPS, which is why everything is going too fast. I'm going to move this "safety" to only be in the web build. The fix will be part of the post-jam version.
Thanks for letting me know! I hope you can still enjoy the web version ;)