Last week there was no progress update because I was in Spain and Andora on a short vacation, but I'm back now, so here's what I did. I added buttons for enabling/disabling music and sound. I added a reset button to restart the current level. The board state gets saved now, so when you close the game and come back to it, you see the tiles as you left them. There's also a win sound when you solve a level and then the board gets locked until you move to another level or reset the current one.
You can play the game here:
https://gamebucket.io/game/b1bd3e0f-3173-4e6a-976b-99535f4a5e16
The link will be active for 30 days.
Next, I'll be thinking of how to make the game more pretty.