It makes a lot of sense if it's two instances loading actually - I haven't found a fix for that web version bug yet, but it's a good start.
There should be a continue button to get back into the game *when it's not broken*. We're reworking the UI at the moment, so I'll fix it if it occasionally breaks!
It should leave that smooth surface on wooden ground tiles - but it shouldn't stay that way if you move that ground tile somewhere else. We have recently fixed this bug and that version will be live soon.
Thanks for your kind words!