I appreciate that! Yes, Mr. Pebbles is quite fast even though he doesn't have any legs.
That is unfortunate. I've seen cursor drifting sometimes while playing some games on Firefox. I think that is some browsers resolution scaling bug, because zooming the browser window to 90% or 110% stopped the drifting for me in all games I've seen it in. Might be something else too in this case though :(
Thanks for playing and for the valuable feedback :)