Played the first 6 or 7 levels. I enjoyed this a lot, and I'm not usually much for puzzle games.
One thing I like is that you let the user undo as many moves as they want, and also that I can retry a puzzle without any kind of feeling that I've failed somehow. I've noticed in a lot of these online puzzle type games like Wordle and its various clones/cousins that the player is often punished somehow for experimenting with the puzzle. This strikes a good balance, where I can fiddle around with the puzzle to my heart's content but still feel satisfied when I get one in the target number of moves.
My idea is that the challenge here is not the time nor getting the puzzle right at first attempt, but as in math problems it's to find the best answer at all eventually.
And if I can't solve some level I can come back to it later (hence the filters for partially completed levels).
One thing I like is that you let the user undo as many moves as they want, and also that I can retry a puzzle without any kind of feeling that I've failed somehow. I've noticed in a lot of these online puzzle type games like Wordle and its various clones/cousins that the player is often punished somehow for experimenting with the puzzle. This strikes a good balance, where I can fiddle around with the puzzle to my heart's content but still feel satisfied when I get one in the target number of moves.
Nice work!