Great work! It’s a fun and relaxing game. I had my fun with the tetris level lol.
Now onto my nitpicks:
I liked the details that the pebbles at the menu screen can be clicked and be played around with. Maybe you can do the same to the pebbles at the level selection also.
Regarding the gameplay, I noticed that you can sort of rotate each pebble by bumping it to the floor or the other pebble. Not sure if it’s part of the intended gameplay, but I think it can be a bit annoying if a pebble rotates in the middle of a level. Maybe you can add the proper way to rotate a pebble.