Your way of slowing down the progress might be even better. I like that you have your own way of thinking! :)
Also many thanks to uploading moving the screen with keyboard. Now I can admire whole design! It is one of the best games I have played recently. Of course it has many ways to improve, but general overview is very good!
Unfortunately I have spot a bug: when you finish the game, you can choose between finishing the board (quit) or staying (resume). If you click resume, the screen stays dark and you can't play any more. (you have to quit anyway)