just downloaded it and man it's making my head hurt so good.
a few flaws:
- when i pick landscape mode or portrait, the game resets the option the next time i open the app.
- any way to reset the whole puzzle? there's only an undo one.
- grey out the numbers when they meet their condition (when a 9 tile has all 9 tiles in the square filled up, the number 9 itself greys out or even becomes green as a green flag).
- better menu scrolling. the "first start" and "story levels" are one and the same. whereas the challenge levels have so many levels under the menu. why not map everything out with icons on the home screen.
other than that? the puzzles are wonderfully thought out. there are a few i would have changed to be introduced sooner when a new mechanic is taught (especially in the "heart" mechanic). but i am in love. wish you could introduce an iap to send a couple of bucks your way as a thank you.