Last updated on December 6th, 2025 at 05:31 pm
SumSudoku: Killer Sudoku – Entertainment Game Review
SumSudoku: Killer Sudoku is a Entertainment/Puzzle/Board game from Conceptis Ltd., first launched in 23rd November 2017.
It’s rated 4+ and currently has 738+ ratings on the App Store.
What Makes SumSudoku: Killer Sudoku Stand Out
Play a crossover variation of Sudoku and Kakuro! SumSudoku, also known as Killer Sudoku, are addictive logic puzzles best described as a cross between Sudoku and Kakuro. Using pure logic and simple add/subtract calculations, these fascinating puzzles offer endless fun and intellectual entertainment to puzzle fans of all skills and ages.
Each puzzle consists of a 9×9 Sudoku grid containing areas surrounded by dark borders. The object is to fill all empty squares so that the numbers 1 to 9 appear exactly once in each row, column and 3×3 box, and the sum of the numbers in each area is equal to the clue in the area's top-left corner. In addition, no number may be used in the same area more than once.
The game includes helpful features such as showing possible sum number combinations in an area and pencilmarks to make temporary placement of numbers in the grid. To help see the puzzle progress, graphic previews in the puzzle list show the progress of all puzzles in a volume as they are being solved. A Gallery view option provides these previews in a larger format.
For more fun, SumSudoku contains no ads and includes a Weekly Bonus section providing an extra free puzzle each week.
PUZZLE FEATURES
• 120 free SumSudoku puzzle samples
• Extra bonus puzzle published free each week
• Multiple difficulty levels from easy to very hard
• Puzzle library continuously updates with new content
• Manually selected, top quality puzzles
• Unique solution for each puzzle
• Hours of intellectual challenge and fun
• Sharpens logic and improves cognitive skills
GAMING FEATURES
• No ads
• Unlimited check puzzle
• Unlimited hints
• Show conflicts during gameplay
• Unlimited Undo and Redo
• Show possible sum combinations option
• Pencilmarks feature for solving hard puzzles
• Autofill pencilmarks mode
• Highlight Excluded Squares option
• Lock number on keypad option
• Concurrently playing and saving multiple puzzles
• Puzzle filtering, sorting and archiving options
• Dark Mode support
• Graphic previews showing puzzles progress as they are being solved
• Portrait and landscape screen support (iPad only)
• Track puzzle solving times
• Backup & restore puzzle progress to iCloud
ABOUT
Conceptis SumSudoku have also become popular under other names such as Killer Sudoku, Sumdoku and Sumoku. All puzzles in this app are produced by Conceptis Ltd. – the leading supplier of logic puzzles to printed and electronic gaming media all over the world. On average, more than 20 million Conceptis puzzles are solved each day in newspapers, magazines, books and online as well as on smartphones and tablets across the world.
This Entertainment game offers engaging gameplay and regular updates for mobile players.
Player Feedback
As a newer release, SumSudoku: Killer Sudoku is building its player community. Early feedback suggests .
Recent Updates & Development
Latest Update: 24th October 2025
Recent improvements include:
This version improves performance and stability.
Download & Availability
SumSudoku: Killer Sudoku is available through the official App Store for iOS devices.
Get SumSudoku: 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:
Also helps with focus. We would suggest you send out some xtra hard games with the free weekly games.
Have the ability to copy numbers from one cell to the next (since deductive reasoning is so prevalent in this game).
Always fun, love the weekly bonuses.
Ive never been disappointed by an app from this developer. Clean, functional, and good in-play instruction and guidance. Highly recommend.
We love this game, takes some time to solve but this is the beauty of it, making our heart peaceful. One function we wish it had was the number of sum is bigger or can be zoomed to see better.
Please add the ability to change the colors! The tan grid lines are very difficult to see. Like several other reviewers have mentioned, it would also be nice to be able to add all 9 notes to the blank cells at one time. Other than those two requests,we are very impressed with the app. It is fun, challenging, and works flawlessly.
This is a good app, but we need to be able to tap once and drag across the notes number pad to add multiple numbers to a cell at once, rather than having to tap each number separately. As is, it's very inefficient and irritating.
This variety of Conceptis puzzle is our absolute favorite. We enjoy every minute we spend, and we spend a lot! Dont like the new color schemes. Even turning off black mode. Theres no distinguishing between completed sets and non completed sets, and the different grays now less appealing and harder to differentiate.
Conceptis makes the BEST sudoku apps. They dont try to gouge you with MTX. They sell puzzles and when you own them they are ACTUALLY YOURS. You can reset them as often as you want and replay them. And they never have ads! This us what apps should be.
We love this app. We are new to SumSudoku and find their easy and medium versions challenging and fun. We are hooked on them. We would like to have a DAILY bonus, not just weekly. We would like to be able to select difficulty levels for the bonus game.
We can now work on these puzzles.
Anything Conceptis is worth getting. We have all their apps (this one is a fav) and have played on them for YEARS. Simple apps, no fancy ads, just lots of puzzles. We buy more packs of puzzles as we need them and often we just repeat the same puzzle packs because Im an ordinary person and its not like we have these puzzles memorized. Im a puzzle nerd and have tried many other apps by other developers but Conceptis is the best.
Well designed game in terms of making the moves. Easy to switch between pen/pencil markings. And the puzzle levels are well defined. Easy is basic enough, medium is a little tricky and the hard puzzles are a real challenge. We like that the game gives your time, and you can restart a puzzle to try to beat your time.
Ive been playing this app for ages and it never gets old. We have a bunch of other puzzle apps and Conceptis apps are our favorites.
We have been using this app for years & appreciate this developers sense of challenge, fun and respect for users privacy.
Although this is not a flashy app, we really enjoy it. It is pure game with simple function (but the game certainly is not simple.) The best part no ads ever! We play it almost every day.
We find regular sudoku puzzles to be too boring at this point, so these puzzles are great at keeping things challenging. We go back and forth between the hard and killer levels, and we find this app more enjoyable and better organized than other apps we have tried.
Some killer Sudoku apps will try to squeeze you for micropayments. And they have no features to let you choose how you want to play. They make things naturally difficult and make you buy undo and other helpful tools. But this one is honest. They sell you groups of puzzles if you want to buy them. And when you buy them, you really own them! You can reset them all and do them again later if you want. This app has great tools and they let you use them all or none. You choose how you play.
Its a good app. Could be better. For example. Why do all of the areas to be summed have to be symmetrical with the other side of the puzzle.
It would be nice for the weekly bonus puzzles to reflect the highest level of difficulty, or at least the 2 highest levels of difficulty the player is using. If you increase the number of puzzles from 30 to 45 or even 50 for the $1.99 it would be great. This is a very good logic and strategy game that is very helpful to maintain brain health. Its appropriate for all age groups. Please decrease the cost. We bet you would sell even more puzzles because we would not have to keep replaying the same games over many times. Do the math evaluate the bottom line effect because money is tight for everyone. Please pay it forward. Its a great game. The update you recently did adding the hint is excellent! Thank you.
We like these types of puzzles, but the hard level does not supply any starting values. Perhaps we have not figured out how to solve them yet, but so far we can only solve these by making generous and unsatisfying use of the guess and check method, rather than just logic.
It never stops asking you to rate/review it. Never. Among the 6 Conceptis apps we have, Ive had to hit No well over 100 times. Every single time they update it and then some. Edit: it asked again Edit 2: it asked again Edit 3: it asked again Edit 4: it asked again Edit 5: it asked again.
The new border around each asymmetrical 9-numbered sectionIts too much. What was wrong with the border thickness before.
We swear, we could get any app from this team and have a blast. This is just about the hardest logic puzzle we've played, and it's great fun. Take it from someone who's been playing Conceptis puzzle games for almost a decade.
Nothing as satisfying as completing a 45 minutes or more pure logic exercise like what these puzzles give you.
We've used this app for killer sudoku for a long time now and it only gets better with each update. The option to autofill the numbers has been great, so has the ability to cross off the fills that you know won't work. We really like the newest update with the assistant that shows you the best next step. It tells you the name of the technique and highlights what to look at. We thought we knew all the tricks but it's taught us a few new ones.
This variety of Conceptis puzzle is our absolute favorite. We enjoy every minute we spend, and we spend a lot.
Hours of sudoku fun for super cheap. We spent $ on 3 package of $2 each so now we have over 100 puzzles we can play over and over and never feel like Im playing the same one twice.
Adds an extra layer of difficulty onto Sudoku, and is a really creative and interesting spin! The app works wonderfully, its very intuitive and Ive encountered no bugs. No ads either, which is very refreshing.
If you love a challenge, this game is addictive!! Im addicted. Nuf said.
Love this app. Its the only one of its kind for SumSudoku.
So much fun. If you like kakuro puzzle, play this one too.
We have a lot of conceptis apps, and we always appreciate how many free puzzles they come with to get you started and how cheap buying additional puzzle packs is. SumSudoku is nice because the puzzles take a lot longer than many of the others – we might be able to do a Hard Nurikabe in 10-15 minutes but a few of the Easy SumSudokus take that long and many of the Hards take a half hour or more. The features included are super helpful – being able to put in number possibilities that automatically disappear when you put another number in, seeing all the instances of a certain number highlighted, etc.
Great puzzles, just the right level of difficulty to be interesting, but not frustrating.
We play this daily and love it. Our favorite variation of Sudoku. Our one wishlist item would be dark mode. At night it is so bright and no color change options available.
We love all the conceptis puzzle apps. Theyre really well made and you get a good variety of puzzle levels in the weekly puzzles. One suggestionI would love a dark mode as we use logic puzzles to help us get sleepy in bed at night.
Ive been playing for almost a year and still havent needed to buy more puzzles but even if we did need to buy more puzzles itd be worth the money to buy them.
SumSudoku, a combination of Kakuro and Sudoku, is absolutely delightful! While we enjoyed both games alone, we really love the bouncing back and forth between the types of logic analysis in solving SumSudoku puzzles. It quickly became our favorite on the iPad. We also really appreciate that they have a killer level of puzzles for those of us who want a significant challenge.
Intimidating at first but after you get the hang of it the challenge is intoxicating. Requires basic math skills and intuitive problem solving skills. Completion of a four or five star puzzle without committing any errors is an awesome accomplishment.
This is the one game app we have paid money for. We woke with words so taking a break by playing with numbers refreshes our brain. Keep adding more, please. $1.99 for at least 12 hours is a steal.
The Killers are the best we've found so far. The only way we could see the interface improving would be with the addition of a 'Lookup' for combinations for any number entered (less than 45 of course) given the number of cells required. Eg., Required Total = 26, Number of cells = 5 This would be similar to the existing facility that shows the combinations for the total of set of linked cells, but we frequently want to know the combinations of the total of a number of unlinked cells as part of nutting out what numbers can go where… Thanks.
Hard ones are really hard and get you thinking – great game.
Im 75 years old, and we can still do most of the killer puzzles without resorting to trial and error. Thats how we know our mind is still OK. Great interface.
Enjoyed. Finally completing Hard. Would enjoy a couple Killer examples. Suggest a one step button to wipe board when we make a mistake.
1) dual input pads – one pad for notes and another for actual input. It saves a lot of time in toggling between the two for a lot of games 2) accurate reverse moves – people will make mistake and can have the comfort that they can restore the original position 3) magic note option – we have it on all the time. It removes the tedious steps in doing everything manual 4) the X button is great because it removes all your personal notes when we make mistake in creating wrong note 5) area calculator to list all possible alternatives Area for improvements: 1) colorize the areas – it is very hard to see the border lines 2) calculator allowing user to input just sum and number of cells. This will compliment the area calculator.
These puzzles exist in other apps and books, but the convenience of the app doing the sums for you and being able to cross them off makes them actually doable.
Need more levels, about to run out of games. Recently changed the button that would erase all pencil to a button that adds all possible marks. It would be nice to have both.
Pretty good program Add more of auto load pencil marks. Allow to select cells and then fill in or take out pencil marks of multiple cells at the same time. If you make a change the auto changer doesnt work right. For example, if you put an 8 in a cell, all the pencil marked cells affected by the 8 are changed. However, if you change that 8 to a 7, those pencil marks arent changed back to 8 unless you use the undo button.
This is the most intuitive layout and best designed puzzles with the fewest gimmicks.
Love your games (we have four of them on our iPad), but today theyre all crashing as soon as we start them. We tried rebooting the device, to no avail. Any solutions.
User feedback from Apple App Store
App Details
- Version: 3.2
- Size: 11.69 MB
- iOS: 12.0 or later
- Languages: EN, JA, KO, ZH
- Content Advisory:
- Developer: Conceptis Ltd.
Last updated: 24th October 2025 | Genre: Entertainment, Puzzle | Developer: Conceptis Ltd.