# Killer Sudoku CTC — user reviews > 60 indexed App Store user reviews of Killer Sudoku CTC by Nick Carney, rated 4.60/5 from 78 ratings. - Source: https://appshunter.io/ios/app/killer-sudoku-ctc/id1544165118/reviews - App overview in markdown: https://appshunter.io/ios/app/killer-sudoku-ctc/id1544165118.md - Rating breakdown: 5★ 63 · 4★ 5 · 3★ 5 · 2★ 1 · 1★ 4 ## What do users think of Killer Sudoku CTC? Overall sentiment: positive **Pros** - ✨ Beautifully crafted puzzles - 🧠 Logically satisfying deductions - 👍 Intuitive and well-designed interface - 💡 Excellent hint system for learning - ✅ Handy calculator and combination lists - 🚀 Smooth gameplay experience - 💯 High-quality app overall - ⭐ Great value for money **Cons** - 🤔 Puzzles can be very difficult - 🐛 Hints sometimes lack clarity - 🐛 Typos and unexplained leaps in hints - 🔋 App can be battery draining - 🔄 Progress lost on reinstallation - ⏳ Slow update frequency - 🤔 Some puzzles require brute force/guessing - 🎨 Limited theme options **Commonly reported bugs** - 🐛 Timer jumps up hundreds of minutes - 🐛 Unusable in landscape mode - 🐛 Puzzles can be unsolvable (e.g., Game #2) - 🐛 Syncing progress resets completion times - 🐛 Undo/redo history lost when exiting game to settings - 🐛 Some themes don't show completed numbers - 🐛 Corner pencil marks display inconsistently **Most requested features** - Ability to reset puzzles - More puzzles needed - Cloud sync feature - Option to view hint and grid simultaneously - Explanation of sudoku terms - Inclusion of list exclusion in undo stack - Darker theme options - Larger buttons for input - Option to see small numbers in order typed - Option to reduce and drag calculator/combinations screen - Shading of cells within the same cage in a different color - Row and column numbers displayed - More color options for cells ## Newest reviews (15 of 60) ### 4/5 — Almost perfect *2024-08-07, version 1.2* The puzzle clears itself the moment you finish it so there’s no time to screen shot the solution. ### 3/5 — Great layout, but some of the puzzles are poorly rated. *2022-07-20* Best interface of any killer sudoku app on the market. Big problem, though. The puzzles authored by “Cracking the Cryptic” are much more difficult than puzzles rated similarly by other authors. Since this was developed by CTC, it would seem that they are not good judges of their own puzzles. It leads to random difficulty spikes that are frustrating for players like myself just learning the ropes. ### 4/5 — Like it! *2022-05-05* Great sudoku app with many well thought out puzzles. One knock is how battery draining the app seems to be. Maybe chosing to build something this simple on Unity was not the right choice? ### 4/5 — What’s an outie? *2022-04-23* How about another option under the settings for an explanation of terms. I’ve googled ‘what’s an outie in sudoku’ and nothing comes up. ### 5/5 — Lovely puzzles *2021-12-05* Love these hand-crafted puzzles though the hard ones are very hard indeed, at least for me. ### 5/5 — Great puzzles, Sometimes hints are not understandable *2021-11-17* I enjoy Cracking The Cryptic variations on Sudoku puzzles and spend more time than I’d like to admit playing them. Sometimes when playing the more difficult puzzles, I look to the hints to get insight as to how to solve them. Many times, the hints are vague and do not help to understand the step. I get that it may be text length limited but if it doesn’t help, why bother. Keep making these puzzles while trying to help with better hints for solutions. ### 5/5 — Nice, but some improvements needed for better UX *2021-11-12* Some useful features: - show the last hint in a small window, so we don't have to navigate forward and back between the hint and the board. (There is unused vertical real estate at the top of the screen) - row and column numbers, so that it's faster to find which row is which for the hints - better themes -- would love a darker dark theme (similar to iOS default dark), or even amoled dark - bigger buttons! It's really hard to press 1-9 properly because the buttons are so small. A mode / layout similar to daily killer sudoku would be really great ### 3/5 — Good puzzles, terrible help *2021-10-13* The puzzles are well designed and extremely challenging! Unfortunately, if you’re not as smart as the Cracking The Cryptic crew, the in-game hints often seem to be focused on conserving space over explaining their logic, which often leads to hints asserting facts not in obvious evidence, which doesn’t help the user understand what they’re doing wrong. ### 4/5 — Mostly Fun, few rough edges *2021-09-08, version 1.1* I’ve really been enjoying this app. It is well made and the puzzles range from easy to very difficult. I’d mostly recommend this. My biggest “complaint” is the hint system. Smart hints are nice, but often will tell me things I already know. “Regular” hints… well they use a lot of jargon and state things that are not obvious and give free explanations. Some puzzles are better than others, but as the difficulty ramps up I’m finding the hints harder to follow. The hint may say these four cells need to be a 6/7/8/9 quadruple or that these two cells must add up to 4, but I have no idea how they got to those limitations. As such, I’m not learning any new strategies. (And sometimes the hints are leave me completely confused.) I did get this app a second time on my android tablet so I could play on a larger screen. Currently the syncing function will sync or merge progress, but it does set your completion times to 999:59 for all your puzzles. (Or at least it did for me.) ### 5/5 — A shame it’s not the top result when searching for Killer Sudoku *2021-06-28* CTC sudoku apps are the only sudoku apps worth installing. High puzzles and apps, should be the first (and only) stop you make when looking for new puzzles to try ### 4/5 — Waiting *2021-06-19* Great games and definitely learnt a lot of new tricks to apply in sudoku. Only wished more levels are released soon as I’m going to forget the tricks or will end up deleting the app after a prolonged period of not playing. ### 5/5 — Tough but excellent puzzles *2021-06-05* A great app for when I’m looking for a really tough puzzle to chew on for an hour. One of the few puzzle apps where I don’t feel too guilty about resorting to a hint now and then. Or if eight or nine minutes go by and I can’t find a logical deduction that’ll move me forward, the app makes it possible to make a guess as to a digit in a particular box and see where it leads. I color the box before I make my guess as to its contents, so that if I reach a contradiction, I can quick undo my moves until the color disappears and I’m back where I started. Very handy. Speaking of hints, though, the first hint in puzzle #22 is in error. One suggestion: When one taps on a box, all the other boxes that that box “sees” are shaded. I’d find it helpful if the other boxes within the same cage could shaded in a slightly different color. ### 5/5 — An app with sense of sudoku romance *2021-06-05* Sudoku setters generate beautiful sudoku and this app has a perfect collection of them ### 5/5 — Top Notch *2021-05-23* I really appreciate all of Cracking the Cryptics sudoku apps, and this is one of my favorites. I enjoy that the puzzles in the beginning teach you the particular logic that you’ll need for more challenging puzzles (like how the first puzzle teaches you to use The Secret). One aspect I really like is the app does a lot of accounting aspects for you, like giving you possible combinations for a given killer cage along with a calculator, plus automatically removing pencil marks that a placed digit interacts with. That is the developers respecting the intelligence of the solver; the challenge is deductions, not getting buried under your pencil marks or petty arithmetic. Top notch app, hats off to the setters who contributed and the development team. ### 3/5 — Alright *2021-05-16* The puzzles are interesting and creative, but some of the hints have typos and make complete lot unexplained leaps of logic. The interface is also a bit clumsy and could do with some polish. If you can overlook these flaws however, the underlying puzzles are solid. ## Most critical reviews (10 lowest-rated) ### 1/5 — Great games but… *2024-11-09, version 1.2* It’s annoying having to replay the same puzzles every time I redownload the app. Sometimes I delete it if I’m spending too much time on it and then I lose all progress. Would much rather have access to all the puzzles at once. ### 1/5 — Unusable after last update *2022-05-06, version 1.2* Love the puzzles in this app, but after the last update, the app is unusable in landscape mode (iphone 13 pro max). Clues are automatically displayed and when they are, they're just a tall and skinny column that you can't even read. It's a small bug that completely destroys the app's usability. ### 1/5 — New puzzle??? *2021-12-13, version 1.1* Hi. New puzzles? They are all done but no update since June!!! Did I pay for something done???? Thx ### 1/5 — 2 major issues stop this being perfect *2021-04-22* I love watching the CTC YouTube channel so have just bought this and completed several puzzles. There are 2 major issues that need resolving: 1) I would like to be able to look at the calc / allowed combinations screen at the same time as looking and completing the puzzle. To do this I’d like there to be an option to reduce the size of the floating calc/combinations screen AND be able to drag it anywhere on the screen so it’s not in the way of the part of the puzzle I’m focusing on 2) I would like the option in the settings that the small numbers I type into a given cell are displayed in the order I type them. So for instance if I type 5142 I would like to see 5142 and not 1245 Otherwise excellent. But these 2 issues mean I can’t enjoy this app until this is resolved. So currently waste of £4.99. I will change this review and star rating if these are both fixed. Thank you ### 1/5 — Pricey, help is sometimes poor *2021-03-26* In this puzzle from CTC there are only few puzzles making it bad value for the price. What I found really frustrating are the hints for some of the puzzles which are not consistent, jumping over relevant steps. I could not follow the logic behind some of the hints. ### 1/5 — Game 2 has bad cages that can’t be solved *2021-01-27, version 1.0* Lower left square has 3 cages with one space left and yet the total is already 45. So can’t solve puzzle 2, which is required to get enough stars to move to puzzle 3. Checked for updates to fix problem but none available. ### 2/5 — Beautiful app, not so good puzzles *2022-02-27, version 1.1* The app is beautiful, however I don’t like the puzzles so much. Most of them require brute force solving. By that I mean you have to take a guess and keep going until you hit a contradiction, then you guess again. ### 2/5 — Marred by niggles *2021-06-16* My favourite form of sudoku, so was really looking forward to CTC version. Great puzzles! But: - navigation between screens is (like the other CTC apps) counter-intuitive at first - typos in some hints (e.g. 26) - several unexplained leaps in hint logic (e.g. Puzzle 18 last hint) - undo/redo history lost if you go out of a game to the settings and back into it again - some themes fail to show when a number has been completed. Oh, and no sign of more puzzles needed to get to having 100 available by the end of the first year. ### 2/5 — Very Slow updates *2021-03-13* Very Slow updates ### 2/5 — Poor readability lets down great game *2020-12-29* I need to start by saying the Killer is my favourite sudoku puzzle type. But the Killer creates the biggest readability challenges, and the app doesn't yet meet the challenge. For those with less than perfect eyesight, even on an ipad it can be difficult to tell apart corner notes from the cage numbers. In landscape mode the grid is smaller than it needs to be: please use some of the spare space to enlarge it. The overlay of the hints, and the additional combination screen in portrait mode is problematic too ... with no ability to move it, it normally obscures the part of the grid you're trying to work on. The navigation between menus in this and the other games in the series is also pretty odd. I'm used to it now, but at first I got confused trying to get back to play the game. As others have said there are also typos, and not all of the controls are explained well to start with. ## Most praised reviews (10 highest-rated) ### 5/5 — Real Excellence! *2024-09-13* After watching the YouTube channel for guidance, I was looking for an app that matched what I saw on the channel as the mobile app I was using was good, but wow…not this good. These puzzles just keep on giving right to the very end! The interface (you can quickly get used to it) is very good indeed, allowing you to focus on the puzzle and not get sidetracked with addition & subtraction. As such, I cannot recommend this app highly enough. ### 5/5 — Best killer audio app I have found *2024-08-12* Great app, hours and hours of curated individual, special puzzles to learn from that get gradually harder with loads of puzzles on the really very hard end of the spectrum. One of my favourite discoveries which I don’t find with any other killer siding puzzles is the realisation that each puzzle has an angle, a thing it is trying to teach you, a technique or an attitude towards solving the puzzles. The interface is very well thought out too. ### 5/5 — Very Enjoyable *2024-07-17* A nice twist on classic Sudoku. I really enjoy the App, the puzzles and the YouTube channel. Lovely. I have spent hours on these wonderful puzzles and they are a bargain all things considered. Thank you CTC and Mr. Carney. ### 5/5 — Great series- but timing bug fix needed *2023-08-05* Love love love the CTC puzzles, but there seems to be a bug with this one where the timer suddenly jumps up 100’s of minutes! Please fix! ### 5/5 — such fun but i need new puzzles *2023-03-26* please release more puzzles i completed them all in an obsession and miss playing so much ### 5/5 — 90 - “Bloom” by Clover *2023-02-24* This puzzle is an absolute work of art. ### 5/5 — Is it possible to reset the puzzles to play them again? *2023-01-29* Love the app, but can’t find a way to reset it and start over again ### 5/5 — The best! *2023-01-26* Hands down the best sudoku app I’ve ever used! Easy, intuitive, and fun!!! ### 5/5 — Beautiful! And a request... *2022-10-18* All of CTC's Sudoku apps have beautiful puzzles and excellent tools. My only request for their Killer (and Sandwich) Sudoku is to include list exclusion (in the given lists of sums) in the undo stack. I will often run aground and need to undo myself back a bit, and I lose my thread of deduction when the lists I've grayed out don't revert. If this is a known challenge for UX (it might appear that nothing happened), I would suggest showing (and flashing?) the sums panel when undoing those exclusions. I give it 5 stars regardless, but knowing how thoughtful they are I thought I would offer this request for future updates! ### 5/5 — The perfect sudoku app! *2022-09-15* Killer sudoku are IMO the best variant, due tom the sheer variety of logical techniques the setter and solver can explore. These puzzles are really fantastic. Every one is thoughtfully crafted, each infused with a delightfully unique structure and narrative. The puzzle interface is simple but effective, with a sophisticated hint system designed to teach new solving techniques. All in all this app feels like a labor of love. Couldn't recommend it more highly. --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-31.*