Last updated on January 17th, 2026 at 04:03 pm
Killer Sudoku! – Puzzle Game Review
Killer Sudoku! is a Puzzle/Education game from Sarah Pierce, first launched in 26th May 2011.
It’s rated 4+ and currently has 1,942+ ratings on the App Store.
What Makes Killer Sudoku! Stand Out
Even better than killer sudoku on paper!
Killer sudoku is a popular variation on classic sudoku puzzles. To complete a puzzle you must fill the board with numbers that obey traditional sudoku rules AND make each outlined region sum to a specific value. The grid begins blank, but these rules give you all the information you need to solve the puzzle!
Solving a killer sudoku puzzle requires a lot of notes, so we worked hard to make the note entry features in this app perfect. A dedicated note keypad and the ability to select multiple squares makes entering notes fast. You can even make combination lists that float above the puzzle and can be rearranged on the screen! Cross out combinations from your lists as you rule them out.
Our interface is so good, you may prefer it to doing puzzles on paper.
Features:
- Dual keypads — no tedious toggling between note and answer mode
- Multi-square note entry — a huge timesaver
- Handy combination lists — can be rearranged on the screen for easy comparison
- Quick sum button — add all selected sum labels instantly
- Quick combination list button — list all combinations fast by dragging over the desired region
- Built-in mini calculator — do even long sums easily
- Undo & redo buttons — step back through your changes to fix a mistake
- Mistake highlighting option — don't let mistyped entries from set you back
- Auto note option — automatically remove trivially eliminated notes when you enter an answer
- Two color schemes — a neutral newspaper color scheme and a rainbow color scheme
- Puzzle gallery — scroll through puzzles and see your progress instantly
- Comes with 10 free puzzles for testing, and over 3,000 puzzles available for purchase
We made this app free so that you can test it without having to buy anything. It comes with ten free killer sudoku puzzles–two puzzles in each of the five levels. There are also more than three thousand puzzles available to purchase, but the ten free puzzles might just keep you busy for a long time :)
All our killer sudoku puzzles have a unique solution.
This Puzzle game offers engaging gameplay and regular updates for mobile players.
Player Feedback
As a newer release, Killer Sudoku! is building its player community. Early feedback suggests .
Recent Updates & Development
Latest Update: 20th June 2020
Recent improvements include:
- Landscape is back on iPad!
- Bug fix for "Puzzle complete" problem
Thank you to everyone who emailed with bug reports and feedback about the recent update. Your emails help me get things fixed faster! Please let me know if you have any issues with the latest version. Best, Sarah
Download & Availability
Killer Sudoku! is available through the official App Store for iOS devices.
Get Killer Sudoku! on App Store
Requirements: Requires iPhone 5s / iPad Air / iPad Air (Cellular) / iPad Mini 2 (Retina) / iPad Mini 2 (Retina, Cellular) / iPhone 6 / iPhone 6 Plus / iPad Air 2 / iPad Air 2 (Cellular) / iPad Mini 3 or later.
Compatible with iPhone and iPad devices.
Player Experience Highlights
Community Insight:
We have played through all the hundreds of puzzles twice and am part way through for a third time. There are too many to remember so why not play them again? They are an escape and almost like meditation in a screwed up world. We can imagine playing them years from now. This is an app that is so well thought out and executed. Thank you for making it such a joy.
Ive love this version of killer sudoku. Purchased all 3 packs and Im almost finished with them on all levels. What will we do when we cant play this?? Please tell us youre working on #4.
Much better than any other killer sudoku app, and killer is much better than regular.
Great app! Excellent functionality, excellent puzzles, all with unique solutions. No annoying ads. Prices for the mega packs are beyond reasonable. Our only request is: Please, please, please release more puzzles! We have been using the app for more than 5 years and have done all of the puzzles multiple times. Having dual keyboardsone for penciling in notes and one for entering final numbersis so much better than having to switch between notes mode and enter mode.
Im pretty sure Ive played all the apps for killer sudoku and this is BY FAR the best. Why? 1. Dual keypads so no tedious switching or mistaken entries 2. Quick combo lists in floating panel with strike through 3. Quick sum any region, e.g. Rule of 45xN 4. Notes are by ENTRY order, not fixed, so you can capture more information, like must-have or subsets This lets you focus on the logic and strategy of solving the puzzle. You dont have to use them if you want to do more mental math. We only use 5 rules to solve any puzzle, and this app interface makes using them elegant: 1. Sudoku rules (1 digit per zone) 2. Naked tuplets 3. Killer rules (region sum and 1 digit per) 4. Rule of 45xN 5. Blocking sets (mutually exclusive combos) Other niceties: NO ADS, rainbow fields to see easier, mini calculator, undo/redo, unlimited in progress puzzles, auto note updates, error checking, and more Only missing feature we would like is ability to highlight digit type across puzzle, including notes, to see patterns easier. Probably tricky with the variable notes which we would not trade. Two slight bugs: strike through misaligned on lists; region sum label is small, blurry (scaled font?) and hard to read sometimes.
Fantastic brain exercise. Easy for when you want to relax. Impossible for when you want a real challenge. And everything in between.
We have played this app for years. It is the only puzzle game we continuously play. We do wish there were more puzzle packs available. We also wish you could reset completed puzzles all at once. We love all the features and ease of use.
If youre addicted to killer sudoku like us, youll enjoy it. The starter puzzles that are free to start with give you a good idea of what to expect, and you can get lots more puzzles for a few bucks. Well worth it. Lots of tools for bookkeeping tasks like adding up a selection of cells, so you determine the values of cells that are extra or are absent in a block, row, or column. Another tool tells all the valid combinations in one cage. The two keyboards, one for pencil marks, the other for pen (final) entries, are a good idea. Clearly a lot of work went into this app. Highly recommended.
Played probably over 100 hours with just a $5 pack (after playing all free puzzles).
Please help! We dont know if we can live without this, but our app keeps crashing since the latest iOS update.
Killer Sudoku is one of our very favorite puzzles, and this version is superb! The only thing we would suggest as an addition would be the ability to highlight numbers on the grid (both notes and filled in).
Best one Ive found. Just wish they had it on android also.
Far and away the best interface Ive seen of online sudokus and sudoku apps.
Ive enjoyed exercising our mind with this game.
This is by far our favorite killer S. Easy to use, no ads, different levels of puzzles, lots of them, great extra features but not intrusive, worth every penny. We have now bought a second bumper pack.
We have played hundreds of puzzles on this app, and cant find any faults in it. With many different levels, clean and clear design, plus the ability to drag across many squares for multi-select to either add / remove multiple numbers at once, or to sum certain combinations together this app has everything you need and want for killer sudoku. Plus having the options to turn on / off hints, color patterns, error checking and auto filling / removing numbers; we recommend this app to everybody.
We love the fact that you can purchase a pack of puzzles without having to subscribe. The features of the game are very nicely designed and Ive never had any trouble with it. We play a lot of puzzle apps, and this one is our favorite.
This is a well-designed app. The puzzles are excellent and the format is easy to learn. A great way to fire up the brain while relaxing and wasting time.
We tried several other KS apps & this is far superior. Clean convenient interface, great range of difficulty. We can barely get through the Impossible level puzzles. No bugs either! (This is MegaFaunas pre-suggested review but honestly it is all quite accurate, so theres no reason to alter it.).
We really enjoy this Killer Sudoku app – we didnt understand how to play it before, but learned by using this app and progressing to harder levels. We play it every night to help us relax – its challenging enough to take our mind off whatever problems Ive that day. Well-designed…we especially love the ability to calculate sums of areas quickly and to list combinations.
Best sudoku there is. It improves with age.
Challenging, makes the brain work! There are levels for everyone. We love this app.
The updated look for the puzzles is great, clean and crisp. It now knows that we are in landscape and rotates the puzzles immediately. Now, if only the other screens were in landscape, too.
We have been playing this virtually every day since it first came out. We have bought all of the game packs and Ive pretty much played through them all twice. We wish there were more packs coming out, but at least they were enough that we can replay them without remembering them. Ive played lots of versions of this, and this instantiation is by far the best. If you like Killer Sudoku, this is a no brainer. We do have one suggestion for the developer though: the new update removes the clock from the upper corner. Any way it can be put back.
This is the best app ever. The layout is crisp and clear and there are plenty of puzzles. Plus, the customer service is amazing and responsive. Highly recommend.
… Back to using the app normally :-).
We have been playing, and addicted to this app for years. The controls, tools, and interface are wonderful. You have everything you need to solve all levels of puzzles right there. We cant say enough about it. Id give it 10 stars if we could! The latest update was missing the ability to play in landscape mode, so we emailed the developer, Sarah Pierce. We got a personal response the next day, and the issue was fixed the very next day!! THAT is amazing customer service!! If youre an experienced sudoku fan, try Killer. You wont regret it! THANK YOU Megafauna and Sarah Pierce.
We submitted a concern about the landscape mode no longer working after the new update. Within hours it was fixed. Along with other things in the game that the update seem to have messed with. We think this is great. We do wish there was a place directly in the game to submit a problem, but as long as someone is listening we guess it doesnt matter. Thank you.
We love this Sudoku game. We love the killer format that uses sums as well as columns/rows/blocks. Its easy to mark notes, check combinations, and check answers. The only thing that might be a minus is that the difficulties dont always seem accurate. But thats really not a problem to worry about.
Loved the app, but since they removed the timer its not nearly as fun. We loved being able to see how much better Ive gotten and trying to top our personal bests.
Simply to use especially when adding options for each cell. Would be helpful to know which numbers have been fully used and a better highlighting when adding in a value when you are crossing grid lines.
Includes some difficult puzzles and a few interesting tools we have not seen in a Sudoku app before. The separate keypads for entering notes and answers are particularly nice.
This game has brought us so much pleasure, and now Ive got our daughter hooked too! Finished all the harder puzzles in all of the packs a few years ago and still re-do them, but would love some new puzzles to be available.
Ive had this app for several years and played it anytime we had time to kill. We have bought all the available packs and just finished the last puzzle available.
This is the only game we still play. But the tiny sums are too small to read – even with cheater glasses.
We love this version. The only things we would change are more puzzles available without purchase. There is no benefit to not guessing, like a limited number of wrong guesses before you have to start again. If there were more puzzles Id have rated it 5 stars. As it stands we finished every available free game in about 2 days.
Pencil marks in most sudoku puzzles automatically place each number in a specific space in the square, but this version puts them in the order typed which gets confusing during game play. For that reason, we deleted the app since other killer apps do.
Inwould rate this app a 5 but suddenly we cant change portrait orientation or get our color theme. Black and white is very hard to see.
We have loved this app and never get tired of playing it. We have purchased all the games! We like the recent update with color added, but now the game skews on our ipad so we have to play it the long way, which means the number pads appear on the right and not below the puzzle. We cannot seem to stop this now and miss the old game system.
Also after new update, besides the usual pleasant colorways and font turning to completely black and white, even the suggested combinations pop ups, everything is difficult to see and VERY rough on the eyes. Now Im also noticing when we exit a puzzle midway, leaving combination pop ups open, we open a different puzzle, even on a different level, and this fully clear new puzzle opens with the overlay of combination popups from the previous puzzle. It was doing this with puzzle completed as well, but Im not seeing it as much now. You had to reload the app each time to make the overlays from previous puzzle go away. We really hope you will bring back the pleasant color and font layout from before that you had for years. It was perfect (and addicting).
This is easily our favorite puzzle app ever, and Ive been more than happy to spend money multiple times over the years on puzzle packs. That being said, Ive spent like 20 dollars on puzzle packs, stop showing us ads for your other apps, we buy into premium apps specifically to avoid apps. Your pop up ads are super irritating because they pop up the instant Im trying to start a puzzle and it backs us out and takes us to the App Store. Im not interested in your other products, Im interested in the one we already purchased.
Great app. Have played for years. BUT, a new update which make it easier by delineating the groups by colour & that automatically deletes the pencilled numbers is plain wrong. Why dumb down the game? So, so, so disappointing. Im almost at the point that we no longer want to play it.
We love this app, and have had it for years, but after our iPhones recent trip to the repair shop that required a reset, the app is not letting us restore the puzzle packs we had already purchased! We need our sudoku! Please fix this so we can give it the 5 stars we used to think it deserved.
Update didnt work Still not fixed. We deleted app and then downloaded again. We should be able to have all puzzles be open to do. But we cant access 98% of them. Still Says in progress on puzzle and cant do anything with it. You didnt fix this. Thx for giving us landscape back. Works better then before. M . Prior comments Its royally screwed up since 6/2020 update.we have enjoyed doing these puzzles for years but 2020 update messes it up big time. 1. Its upside down now for those of us still on iPhone 8. 2. Can no longer use it on landscape which makes it difficult and bad for your hands and fingers on a iPad. 3. Your old font was better and easier on the eyes. 4. The green you chose isnt easy on the eyes. It stresses them. Too brighta. Needs more matte 5. Worst is that you keep saying a puzzle is completed but you havent played it after renewing it. People play the puzzles over and over after purchasing them. And 6. And if it is completed why has it not been taken off the open puzzle list??? Like it always has been. You rushed your redo. Not a good thing for the user. Please spend some more time and more care on this update. Thx. It would wonderful to be able to play it again with outall the problems.
Ive had this app for a long time as its the best killer sudoku Ive had. But the new UI makes it even better.
Love this game. Time for new puzzles.
Best Sumdoku puzzle game out there. Only two (minor) things stop us from giving it a perfect score. First, there have been way too many times when we have hit the wrong keypad and accidentally gave ourselves the answer to a square. And second, this last update took away landscape mode. We play this on our iPad, and landscape is a lot better than portrait view. Thanks for a fun game.
We love the game but find it easier to use in landscape mode which appears to have been removed in the latest update.
Was one of our favorite apps till last update. No longer can play holding our screen horizontal. All puzzles now show puzzle completed and can no longer be played.
So many bugs in the newest version.
User feedback from Apple App Store
App Details
- Version: 4.1
- Size: 13.08 MB
- iOS: 9.0 or later
- Languages: EN
- Content Advisory:
- Developer: [Sarah Pierce]()
Last updated: 20th June 2020 | Genre: Puzzle, Education | Developer: Sarah Pierce