★★★★★ Missing a Key Feature
Wed Apr 23 2025 RaccooninyourtrashI saw the reviews, decided to try anyway because it’s the only Sudoku app I’ve seen that lets you create games. The problem is that with ever other Sudoku app, they let you mark down all possible numbers for any given spot. This is usually why I like Sudoku apps over pen and paper because I’m not marking up my pages just to keep track.
This one, for whatever reason, doesn’t seem to have that? I don’t know if I just can’t find it or if it’s just not there, but I’m going to assume if they aren’t going to make it obvious how to find it, then it’s likely not there. If it’s added, then I would be all for it, buuut it somehow feels incredibly lacking for an app with a price point.
★★★★★ Fantastic App
Fri Dec 24 2021 stepwiseclicheIt gets 5 stars for being the only app of its kind on iOS to allow solving puzzles from all over the internet. Previously, I had a huge bookmark folder of puzzles I had to wait until I was on a desktop to solve, but now I can solve them on my phone, and that is a beautiful thing.
Some suggestions: The process of cleaning up pencilmarks can be rather tedious, so auto-pencilmark elimination in row/column when placing digits would be a very nice feature to have as something that could be enabled in settings.
Also, while long pressing on a cell highlight similar cells, it would be nice to be able to do this highlighting from the number pad with a long press. For example, if I wanted to highlight all cells with corner marked 5s, I could go to corner marks and hold the 5 button to do so. Currently, I have to have a corner marked 5 with no other corner marks to highlight just the 5s.
Some sort of cloud syncing would also be nice so people could continue playing puzzles on different devices. Those features missing aside, this is still the best iOS app for solving sudokus and has earned all 5 of these stars until that stops being true.
Edit: also auto-pausing the clock when switching apps would be good. There is some glitchy behavior with the clock in general, but I am not personally reliant on it.
★★★★★ Favorite Sudoku App
Sat Dec 20 2025 ktviaObviously if you have this app, you know cracking the cryptic. I find that most of the complaints are that there is only a limited set of puzzles (true) but since its more of an importer app for cracking the cryptic + a few puzzles, this isn’t really a problem. I’ve solved hundreds of puzzles because the UI for this app is just simply perfect. The fact that you have two versions of notes, you can color the boxes, you can highlight multiple numbers at the same time.. to die for! I’ve genuinely ely had no regrets buying this and have been using it for years lol. This is also my first app review (at least from what I remember) but I feel the need to review because I love love this app so much.
★★★★★ Excellent, but outdated
Tue Nov 15 2022 Ian DenkerThis is a wonderful app to solve the puzzles featured on the channel, however, there's some key features in the web app that are missing from this. Notably, the letter function, the extra colors, diagonal lines on the line tool, and the new fog of war mechanic are missing. The latter is, albeit, quite new, but seeing as this hasn't been updated in 11 months, adding at least some of the new things would be great. Additionally, the ability to detect if a solution is correct for irregular or otherwise "non-normal" sudoku puzzles would be most welcome. When I do complete one of those, it is often marked as wrong and therefore incomplete, so I usually just delete it from the app.
Overall though, it works superbly well for almost every puzzle!
★★★★★ Almost everything you could want
Sun Oct 03 2021 My.Humble.Opinion**Strengths: This is easily the best way to solve a Sudoku puzzle whether it is one from CtC or one from another source. I had been hoping for something like it since I first used the CtC web app for the videos. Very easy to use and makes me want to solve more puzzles again after putting them down a few months ago.
**Areas for improvement: It would be very helpful if it had the ability to use the phone camera to autodetect a puzzle that is on paper instead of having to manually enter each number in a custom puzzle. It would also help if the timer automatically paused if switching to another app or turning off the phone.
★★★★★ A Few Requests
Mon Jan 31 2022 rmdkvoeknsjddI love CTC and I love the dual pencil notation idea of Sven’s solver. However, there are a few quirks I think could be improved. Double-tapping an empty cell deselects everything else, but the taps have to be spaced precisely for this to work. There is a little empty space in the bottom left corner of the screen, maybe tapping there could unselect everything.
I would LOVE a way to select all pencil marks of a certain candidate. The other CTC apps do this and it’s very convenient.
Double-tapping a filled cell highlights all cells of that number. This is helpful, but it would be great if selecting a digit in the number pad did this. Maybe each “version” of the number pad (number, corner marks, and center marks) could highlight all candidates of that type.
This app is SO CLOSE to being the perfect solver, especially with the ability to enter puzzles. I agree with the other reviewer that an auto-detector would be amazing, but not necessary for a perfect app. The suggestions above (especially the ability to highlight all of a particular candidate) would make it a perfect solver.
Thanks Sven!
★★★★★ Great Sudoku app, but DESPERATELY needs an update
Thu Jul 31 2025 tjhThis is a great app for creating and solving hand-crafted puzzles. Puzzles are stored locally, offline, and completion times are stored, so you can build up a nice library of puzzles, abandon a puzzle and pick up where you left off weeks or months later, and compete against your best times.
The app offers three kinds of in-cell notes, one using color and two different ways of notating numbers.
However, this iOS app has fallen far behind the web app in features, and some of the puzzles available for download into the app are much harder to solve in this version. Additionally, some features appear to be broken. Most seriously, the feature that shows the defined rules for a particular puzzle rarely transfer over to the app, leaving the user guessing what the correct rules is.
Unfortunately, the web app does not scale nicely to mobile touch interfaces and provides no mechanism for saving puzzles.
This app needs an update.
★★★★★ Missing many features in puzzle setting mode, no variants
Thu Dec 30 2021 LMMQAExtremely disappointed with this app. I was hoping I could use it to build puzzles but this was clearly not designed for that purpose. In the puzzle setting mode you can’t add corner or center pencil marks or color cells different colors.
The only think keeping this from a 1 star review is that it does have some good puzzles built in for you to solve, but there just aren’t enough of them.
One other complaint - with this app being associated with Cracking the Cryptic, I expected some puzzles to feature sudoku variant rules, or the puzzle setting mode to allow adding custom rules and features to your puzzles (killer cages, thermos, etc.) but no, it’s classics only.
Not worth the $5. It would be okay if it started free and featured only the classic puzzles, and the variants and additional classics would be locked behind a $5 paywall.
If you’re looking for classic sudoku puzzles to solve, just watch the Cracking the Cryptic videos on classic puzzles and solve those. If you’re looking for a puzzle setting tool, just use f-puzzles or penpa.
