The puzzles don’t seem to really increase in difficulty, exactly. None are too hard, and all are pleasing to complete. Was hard to tell the blues apart until I realized one has a little bit of purple in it. I would like a little more challenge, more versions perhaps, too, like having to put something on every square, and I wish there were something open ended where one can just build and play with all pieces. Would be handy if one could keep the pieces off the board, like in a side tray, but perhaps having to move them out of the way and watch that they don’t prevent triggered shifting pieces is an intentional challenge, and I still love this game, more than any other app I’ve ever tried. That’s not saying a lot, bc most apps just try to get you to pay a lot of money to still not get anywhere and therefore aren’t fun at all, but still, I love this game.