Ah, now that you say it, a level reset button would be super easy to implement and convenient.
On your first point, the "destroy mode" can be activated with "X" or "Del" key, and then you can click to destroy. I couldn't get a control screen done in time so I added that to ArbyG's dialogue (which, if you played it too early, wasn't in the game due to a bug that has been fixed).
Thanks so much for giving it a go!