4 stars: Absolutely love the settings and features you can use. Way better format than any other app for sudoku I've used. The only reason I gave it 4 stars instead of 5 is because I wish that the puzzles were more difficult. Even on extreme it ussually only takes me 10 minutes to solve without any help or hints.
3 stars: 11/7/17 edit: I like being able to highlight cross hairs. What I really want is to add highlights manually to mark out other impossibilities. 11/3/15 edit. Yes, you can use cross hairs, which is great! But still can't highlight other impossibilities. UI is nice though. Original: Why oh why oh why can't I find a Sudoku that will allow me to highlight rows and columns? My very very old palm pilot had a game that did just that. Really helped me learn to play, and it's faster to see patterns, double check yourself. So hard to find now.
4 stars: I love this game, but the ads need better monitoring. It just dropped down a porn site from the ad at the top of my screen. It took 6-8 tries to back out of it, but each time it loaded a new porn site. I'm not sure, but one could have been a child. Update 8/28/17 the ads are monitored better or something. No more disturbing sites.
3 stars: I've been playing this game for years and suddenly in the past weeks (not sure exactly when) I'm beating the Extreme games as if they're Medium. I've cut all my Top 10 times in half. I don't think I've suddenly become that much better. I've had this app for a few year...