Those are very strange movement and input bugs you described. No, none of that is intended and I haven't seen or heard about any of that behavior before. Honestly, I'm impressed you stuck with it, that sounds frustrating.
Were you playing in WebGL? That can cause some weird issues, especially with mouse sensitivity, because of how it buffers frames. I would recommend trying out the Windows build if you run Windows, this game is frankly just a bit too much for most Browsers, but I put it up there anyways for convenience sake.