Aha that's why it wasn't working for me, I guess the browser version is broken then :(
Yeah, we realised too late that we were doing the mouse input on the wrong game tick – which is what causes the mouse-aim issues + it only seems to show up on the web version + it also seems to only happen for some people!
Either using a gamepad/controller or running one of the desktop builds is the only solution we have until after the voting period I’m afraid :/